Compositions for containers and other articles and methods of using same

ABSTRACT

This invention provides a polymer, which is preferably a polyether polymer. The polymer may be uses in coating compositions. Containers and other articles comprising the polymer and methods of making such containers and other articles are also provided. The invention further provides compositions including the polymer (e.g., powder coatings), which have utility in a variety of coating end uses, including, for example, valve and pipe coatings.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.15/570,632 filed on Jul. 7, 2016 and entitled “COATING COMPOSITION FORCONTAINERS AND OTHER ARTICLES AND METHODS OF COATING”, which is acontinuation of U.S. application Ser. No. 13/570,632 filed on Aug. 9,2012 and entitled “COATING COMPOSITION FOR CONTAINERS AND OTHER ARTICLESAND METHODS OF COATING” (now U.S. Pat. No. 9,409,219), which is acontinuation-in-part of International Application Nos. PCT/US2012/024191and PCT/US2012/024193, which were both filed on Feb. 7, 2012 andentitled “COATING COMPOSITION FOR CONTAINERS AND OTHER ARTICLES ANDMETHODS OF COATING,” each of which claims the benefit of U.S.Provisional Application No. 61/440,085 filed on Feb. 7, 2011 andentitled “COATING COMPOSITION FOR CONTAINERS AND OTHER ARTICLES ANDMETHODS OF COATING,” and U.S. Provisional Application No. 61/579,072filed on Dec. 22, 2011 and entitled “COATING COMPOSITION FOR CONTAINERSAND OTHER ARTICLES AND METHODS OF COATING,” each of which isincorporated herein by reference in its entirety.

BACKGROUND

The application of coatings to metals to retard or inhibit corrosion iswell established. This is particularly true in the area of packagingcontainers such as metal food and beverage cans. Coatings are typicallyapplied to the interior of such containers to prevent the contents fromcontacting the metal of the container. Contact between the metal and thepackaged product can lead to corrosion of the metal container, which cancontaminate the packaged product. This is particularly true when thecontents of the container are chemically aggressive in nature.Protective coatings are also applied to the interior of food andbeverage containers to prevent corrosion in the headspace of thecontainer between the fill line of the food product and the containerlid.

Packaging coatings should preferably be capable of high-speedapplication to the substrate and provide the necessary properties whenhardened to perform in this demanding end use. For example, the coatingshould be safe for food contact, not adversely affect the taste of thepackaged food or beverage product, have excellent adhesion to thesubstrate, resist staining and other coating defects such as “popping,”“blushing” and/or “blistering,” and resist degradation over long periodsof time, even when exposed to harsh environments. In addition, thecoating should generally be capable of maintaining suitable filmintegrity during container fabrication and be capable of withstandingthe processing conditions that the container may be subjected to duringproduct packaging.

Various coatings have been used as interior protective can coatings,including polyvinyl-chloride-based coatings and epoxy-based coatingsincorporating bisphenol A (“BPA”). Each of these coating types, however,has potential shortcomings. For example, the recycling of materialscontaining polyvinyl chloride or related halide-containing vinylpolymers can be problematic. There is also a desire by some to reduce oreliminate certain BPA-based compounds commonly used to formulatefood-contact epoxy coatings.

What is needed in the marketplace is an improved binder system for usein coatings such as, for example, packaging coatings.

SUMMARY

This invention provides a polymer useful in a variety of applications,for example, as a binder polymer of a coating composition. In preferredembodiments, the polymer does not include any structural units derivedfrom bisphenol A (“BPA”), bisphenol F (“BPF”), bisphenol S (“BPS”), orany diepoxides thereof (e.g., diglycidyl ethers thereof such as thediglycidyl ether of BPA (“BADGE”)). In addition, the polymer preferablydoes not include any structural units derived from a dihydric phenol, orother polyhydric phenol, having estrogenic agonist activity greater thanor equal to that of 4,4′-(propane-2,2-diyl)diphenol. More preferably,the polymer does not include any structural units derived from adihydric phenol, or other polyhydric phenol, having estrogenic agonistactivity greater than or equal to that of BPS. Even more preferably, thepolymer does not include any structural units derived from a dihydricphenol, or other polyhydric phenol, having estrogenic agonist activitygreater than 4,4′-(propane-2,2-diyl)bis(2,6-dibromophenol). Optimally,the polymer does not include any structural units derived from adihydric phenol, or other polyhydric phenol, having estrogenic agonistactivity greater than 2,2-bis(4-hydroxyphenyl)propanoic acid. The sameis preferably true for any other components of a composition includingthe polymer.

In some embodiments, the polymer is a polyether polymer that contains aplurality of aromatic ether segments. The polyether polymer may beformed, for example, from reactants including a polyhydric phenol (moretypically a dihydric phenol) and a polyepoxide of a polyhydric phenol(more typically a diepoxide of a dihydric phenol). While not intendingto be bound by any theory, one or more of the following structuralcharacteristics may help avoid undesirable estrogenic agonist activityshould any residual unreacted polyhydric phenol persist: the presence of“bulky” substituent groups, molecular weight (e.g., of the “bridge”region of a bisphenol), and the presence of polar groups.

Preferred polymers of the present invention are suitable for use in avariety of end uses, including as a film-forming material of a coating.In some such embodiments, the polymer has a glass transition temperature(“Tg”) of at least 30° C., more preferably at least 60° C., and a numberaverage molecular weight of at least 1,000 or at least 2,000. Aryl orheteroaryl groups preferably constitute at least 25 weight percent ofthe polymer.

In some embodiments, the polymer preferably includes one or moresegments having one or more optionally substituted aryl or heteroarylgroups in a backbone portion of the segment. In some embodiments, theone or more such aryl or heteroaryl groups include one or moresubstituent groups (preferably “bulky” substituent groups) that areattached to the ring preferably at an ortho or meta position, morepreferably an ortho position, relative to an oxygen atom attached to thering, which is typically an oxygen atom of an ether or ester linkage,more typically an ether linkage. In some embodiments, the one or moresegments include two or more aryl or heteroaryl groups in which at leasttwo of the aryl or heteroaryl groups include an oxygen atom attached tothe ring and a substituent group (preferably a “bulky” substituentgroup) attached to the ring preferably at an ortho or meta positionrelative to the oxygen atom. Examples of suitable such segments include:—O—Ar—((R²)_(n)—Ar)_(t)—O—, wherein “Ar” represents an aryl orheteroaryl group preferably having at least one R¹ group attached to thering at an ortho or meta position relative to the depicted oxygen atom,which preferably belongs to an ether linkage, and wherein R¹, R², n, andt are as defined herein for Formula (I). In preferred embodiments, thepolymer is a polyether polymer.

In preferred embodiments, the polymer includes one or more segments, andeven more preferably a plurality of segments, of the below Formula (I):

wherein:

-   -   each of the pair of oxygen atoms depicted in Formula (I) is        preferably present in an ether or ester linkage, more preferably        an ether linkage;    -   H denotes a hydrogen atom, if present;    -   each R¹ is independently an atom or group preferably having an        atomic weight of at least 15 Daltons, wherein each of the        phenylene groups depicted in Formula (I) preferably includes at        least one R¹ attached to the phenylene ring at an ortho or meta        position relative to the oxygen atom;    -   v is independently 0 to 4, more preferably 1 to 4, even more        preferably 2 to 4;    -   w is 4;    -   R², if present, is preferably a divalent group;    -   n is 0 or 1, with the proviso that if n is 0, the phenylene        groups depicted in Formula (I) can optionally join to form a        fused ring system with each other (e.g., a substituted        naphthalene group), in which case w is 3 (as opposed to 4) and v        is 0 to 3 (as opposed to 0 to 4);    -   t is 0 or 1; and    -   wherein two or more R¹ and/or R² groups can join to form one or        more cyclic groups.

When t is 1, the segment of Formula (I) is a segment of the belowFormula (IA).

When t is 0, the segment of Formula (I) is a segment of the belowFormula (IB).

The segment of Formula (I) preferably includes at least one R¹ that iscapable of providing steric hindrance to a phenol hydroxyl group. Morepreferably, each phenylene group depicted in Formula (IA) includes atleast one such R¹ group, even more preferably includes at least two suchR¹ groups. Preferred such R¹ groups are sufficiently “bulky” so that,when located at an ortho or meta position (more typically an orthoposition) relative to a phenol hydroxyl group, the R¹ group providessufficient steric hindrance to eliminate or reduce any undesirable levelof estrogenic agonist activity associated with a polyhydric phenolincluding a segment of Formula (I).

In certain preferred embodiments, one or both of the following are true:(i) at least one R¹ is attached to each phenylene ring depicted inFormula (IA) at an ortho position relative to the depicted oxygen atomand (ii) at least one R¹ attached to the ring at an ortho or metaposition relative to the depicted oxygen atom includes one or morecarbon atoms. Non-limiting examples of R¹ groups include groups havingat least one carbon atom, a halogen atom, a sulfur-containing group, orany other suitable group preferably having an atomic weight of at least15 Daltons that is preferably substantially non-reactive with an epoxygroup. Organic groups are presently preferred, with organic groups thatare free of halogen atoms being particularly preferred.

In preferred embodiments, the polymer also includes pendant hydroxylgroups (e.g., secondary hydroxyl groups) and, more preferably, one ormore —CH₂—CH(OH)—CH₂— or —CH²—CH₂—CH(OH)— segments, which are preferablyderived from an oxirane and located in a backbone of the polymer.

The present invention also provides a coating composition that includesthe polymer described herein, more preferably a polyether polymerdescribed herein. The coating composition preferably includes at least afilm-forming amount of the polymer and may optionally include one ormore additional polymers. The coating composition is useful in coating avariety of substrates, including as an interior or exterior coating onmetal packaging containers or portions thereof. In preferredembodiments, the coating composition is useful as a food-contact coatingon a food or beverage container. In preferred embodiments, the coatingcomposition is at least substantially free of mobile BPA or BADGE, andmore preferably is completely free of BPA or BADGE. More preferably, thecoating composition is at least substantially free, and more preferablycompletely free, of mobile or bound polyhydric phenols having estrogenicagonist activity greater than or equal to that of4,4′-(propane-2,2-diyl)diphenol. Even more preferably, the coatingcomposition is at least substantially free, and more preferablycompletely free, of mobile or bound polyhydric phenols having estrogenicagonist activity greater than or equal to that of BPS. Even morepreferably, the coating composition is at least substantially free, andmore preferably completely free, of mobile or bound polyhydric phenolshaving estrogenic agonist activity greater than that of4,4′-(propane-2,2-diyl)bis(2,6-dibromophenol). Optimally, the coatingcomposition is at least substantially free, and more preferablycompletely free, of mobile or bound polyhydric phenols having estrogenicagonist activity greater than about that of2,2-bis(4-hydroxyphenyl)propanoic acid). The coating composition mayalso have utility in a variety of other coating end uses, including, forexample, coatings for valves and fittings, especially valves andfittings for use with potable water, pipes for conveying liquids,especially potable water pipes; and liquid storage tanks, especiallypotable water tanks, e.g., bolted steel water tanks.

In one embodiment, the coating composition of the present invention is apowder coating composition that preferably includes a base powder,formed at least in part, from the polymer of the present invention. Thecoating composition may include one or more optional ingredients in theparticles of the base powder and/or in a separate particle. Suchoptional ingredients may include, for example, crosslinker, cureaccelerator, colored pigment, filler, flow additives, etc.

The present invention also provides packaging articles having a coatingcomposition of the present invention applied to a surface of thepackaging article. In one embodiment, the packaging article is acontainer such as a food or beverage container, or a portion thereof(e.g., a twist-off closure lid, beverage can end, food can end, etc.),wherein at least a portion of an interior surface of the container iscoated with a coating composition described herein that is suitable forprolonged contact with a food or beverage product or other packagedproduct.

In one embodiment, a method of preparing a container is provided thatincludes an interior, food-contact coating of the present invention. Themethod includes: providing a coating composition described herein thatincludes a binder polymer and optionally a liquid carrier; and applyingthe coating composition to at least a portion of a surface of asubstrate prior to or after forming the substrate into a container or aportion thereof having the coating composition disposed on an interiorsurface. Typically, the substrate is a metal substrate, although thecoating composition may be used to coat other substrate materials ifdesired. Examples of other substrate materials may include fiberboard,plastic (e.g., polyesters such as, e.g., polyethylene terephthalates;nylons; polyolefins such as, e.g., polypropylene, polyethylene, and thelike; ethylene vinyl alcohol; polyvinylidene chloride; and copolymersthereof) and paper.

In one embodiment, a method of forming food or beverage cans, or aportion thereof, is provided that includes: applying a coatingcomposition described herein to a metal substrate (e.g., applying thecoating composition to the metal substrate in the form of a planar coilor sheet), hardening the coating composition, and forming the substrateinto a food or beverage can or a portion thereof.

In certain embodiments, forming the substrate into an article includesforming the substrate into a can end or a can body. In certainembodiments, the article is a two-piece drawn food can, three-piece foodcan, food can end, drawn and ironed food or beverage can, beverage canend, easy open can end, twist-off closure lid, and the like. Suitablemetal substrates include, for example, steel or aluminum.

In certain embodiments, a packaging container is provided having: (a) acoating composition of the present invention disposed on at least aportion of an interior or exterior surface of the container and (b) aproduct packaged therein such as a food, beverage, cosmetic, ormedicinal product.

In one embodiment, a packaging container having a coating composition ofthe present invention disposed on an interior surface is provided thatincludes a packaged product intended for human contact or consumption,e.g., a food or beverage product, a cosmetic product, or a medicinalproduct.

The above summary of the present invention is not intended to describeeach disclosed embodiment or every implementation of the presentinvention. The description that follows more particularly exemplifiesillustrative embodiments. In several places throughout the application,guidance is provided through lists of examples, which examples can beused in various combinations. In each instance, the recited list servesonly as a representative group and should not be interpreted as anexclusive list. Unless otherwise indicated, the structuralrepresentations included herein are not intended to indicate anyparticular stereochemistry and are intended to encompass allstereoisomers.

Definitions

As used herein, the term “organic group” means a hydrocarbon group (withoptional elements other than carbon and hydrogen, such as oxygen,nitrogen, sulfur, and silicon) that is classified as an aliphatic group,a cyclic group, or combination of aliphatic and cyclic groups (e.g.,alkaryl and aralkyl groups).

The term “cyclic group” means a closed ring hydrocarbon group that isclassified as an alicyclic group or an aromatic group, both of which caninclude heteroatoms.

The term “alicyclic group” means a cyclic hydrocarbon group havingproperties resembling those of aliphatic groups.

The term “aryl group” (e.g., an arylene group) refers to a closedaromatic ring or ring system such as phenylene, naphthylene,biphenylene, fluorenylene, and indenyl, as well as heteroarylene groups(e.g., a closed aromatic or aromatic-like ring hydrocarbon or ringsystem in which one or more of the atoms in the ring is an element otherthan carbon (e.g., nitrogen, oxygen, sulfur, etc.)). Suitable heteroarylgroups include furyl, thienyl, pyridyl, quinolinyl, isoquinolinyl,indolyl, isoindolyl, triazolyl, pyrrolyl, tetrazolyl, imidazolyl,pyrazolyl, oxazolyl, thiazolyl, benzofuranyl, benzothiophenyl,carbazolyl, benzoxazolyl, pyrimidinyl, benzimidazolyl, quinoxalinyl,benzothiazolyl, naphthyridinyl, isoxazolyl, isothiazolyl, purinyl,quinazolinyl, pyrazinyl, 1-oxidopyridyl, pyridazinyl, triazinyl,tetrazinyl, oxadiazolyl, thiadiazolyl, and so on. When such groups aredivalent, they are typically referred to as “arylene” or “heteroarylene”groups (e.g., furylene, pyridylene, etc.)

A group that may be the same or different is referred to as being“independently” something. Substitution on the organic groups of thecompounds of the present invention is contemplated. As a means ofsimplifying the discussion and recitation of certain terminology usedthroughout this application, the terms “group” and “moiety” are used todifferentiate between chemical species that allow for substitution orthat may be substituted and those that do not allow or may not be sosubstituted. Thus, when the term “group” is used to describe a chemicalsubstituent, the described chemical material includes the unsubstitutedgroup and that group with O, N, Si, or S atoms, for example, in thechain (as in an alkoxy group) as well as carbonyl groups or otherconventional substitution. Where the term “moiety” is used to describe achemical compound or substituent, only an unsubstituted chemicalmaterial is intended to be included. For example, the phrase “alkylgroup” is intended to include not only pure open chain saturatedhydrocarbon alkyl substituents, such as methyl, ethyl, propyl, t-butyl,and the like, but also alkyl substituents bearing further substituentsknown in the art, such as hydroxy, alkoxy, alkylsulfonyl, halogen atoms,cyano, nitro, amino, carboxyl, etc. Thus, “alkyl group” includes ethergroups, haloalkyls, nitroalkyls, carboxyalkyls, hydroxyalkyls,sulfoalkyls, etc. On the other hand, the phrase “alkyl moiety” islimited to the inclusion of only pure open chain saturated hydrocarbonalkyl substituents, such as methyl, ethyl, propyl, t-butyl, and thelike. As used herein, the term “group” is intended to be a recitation ofboth the particular moiety, as well as a recitation of the broader classof substituted and unsubstituted structures that includes the moiety.

The term “polyhydric phenol” (which includes dihydric phenols) as usedherein refers broadly to any compound having one or more aryl orheteroaryl groups (more typically one or more phenylene groups) and atleast two hydroxyl groups attached to a same or different aryl orheteroaryl ring. Thus, for example, both hydroquinone and 4,4′-biphenolare considered to be polyhydric phenols. As used herein, polyhydricphenols typically have six carbon atoms in an aryl ring, although it iscontemplated that aryl or heteroaryl groups having rings of other sizesmay be used.

The term “phenylene” as used herein refers to a six-carbon atom arylring (e.g., as in a benzene group) that can have any substituent groups(including, e.g., hydrogen atoms, halogens, hydrocarbon groups, oxygenatoms, hydroxyl groups, etc.). Thus, for example, the following arylgroups are each phenylene rings: —C₆H₄—, —C₆H₃(CH₃)—, and —C₆H(CH₃)₂Cl—.In addition, for example, each of the aryl rings of a naphthalene groupare phenylene rings.

The term “substantially free” of a particular mobile or bound compoundmeans that the recited material or composition contains less than 1,000parts per million (ppm) of the recited mobile or bound compound. Theterm “essentially free” of a particular mobile or bound compound meansthat the recited material or composition contains less than 100 partsper million (ppm) of the recited mobile or bound compound. The term“essentially completely free” of a particular mobile or bound compoundmeans that the recited material or composition contains less than 5parts per million (ppm) of the recited mobile or bound compound. Theterm “completely free” of a particular mobile or bound compound meansthat the recited material or composition contains less than 20 parts perbillion (ppb) of the recited mobile or bound compound. If theaforementioned phrases are used without the term “mobile” or “bound”(e.g., “substantially free of BPA”), then the recited material orcomposition contains less than the aforementioned amount of the compoundwhether the compound is mobile or bound.

The term “mobile” means that the compound can be extracted from thecured coating when a coating (typically ˜1 mg/cm²) is exposed to a testmedium for some defined set of conditions, depending on the end use. Anexample of these testing conditions is exposure of the cured coating toHPLC-grade acetonitrile for 24 hours at 25° C.

The term “bound” when used in combination with one of the aforementionedphrases in the context, e.g., of a bound compound of a polymer or otheringredient of a coating composition (e.g., a polymer that issubstantially free of bound BPA) means that the polymer or otheringredient contains less than the aforementioned amount of structuralunits derived from the compound. For example, a polymer that issubstantially free of bound BPA includes less than 1,000 ppm (or 0.1% byweight), if any, of structural units derived from BPA.

When the phrases “does not include any,” “free of” (outside the contextof the aforementioned phrases), and the like are used herein, suchphrases are not intended to preclude the presence of trace amounts ofthe pertinent structure or compound which may be present due toenvironmental contaminants.

The terms “estrogenic activity” or “estrogenic agonist activity” referto the ability of a compound to mimic hormone-like activity throughinteraction with an endogenous estrogen receptor, typically anendogenous human estrogen receptor.

The term “food-contact surface” refers to the substrate surface of acontainer (typically an inner surface of a food or beverage container)that is in contact with, or intended for contact with, a food orbeverage product. By way of example, an interior surface of a metalsubstrate of a food or beverage container, or a portion thereof, is afood-contact surface even if the interior metal surface is coated with apolymeric coating composition.

The term “unsaturated” when used in the context of a compound refers toa compound that includes at least one non-aromatic double bond.

The term “crosslinker” refers to a molecule capable of forming acovalent linkage between polymers or between two different regions ofthe same polymer.

The term “on,” when used in the context of a coating applied on asurface or substrate, includes both coatings applied directly orindirectly to the surface or substrate. Thus, for example, a coatingapplied to a primer layer overlying a substrate constitutes a coatingapplied on the substrate.

Unless otherwise indicated, the term “polymer” includes bothhomopolymers and copolymers (e.g., polymers of two or more differentmonomers). Similarly, unless otherwise indicated, the use of a termdesignating a polymer class such as, for example, “polyether” isintended to include both homopolymers and copolymers (e.g.,polyether-ester copolymers).

The terms “comprises” and variations thereof do not have a limitingmeaning where these terms appear in the description and claims.

The terms “preferred” and “preferably” refer to embodiments of theinvention that may afford certain benefits, under certain circumstances.However, other embodiments may also be preferred, under the same orother circumstances. Furthermore, the recitation of one or morepreferred embodiments does not imply that other embodiments are notuseful, and is not intended to exclude other embodiments from the scopeof the invention.

As used herein, “a,” “an,” “the,” “at least one,” and “one or more” areused interchangeably. Thus, for example, a coating composition thatcomprises “a” polyether can be interpreted to mean that the coatingcomposition includes “one or more” polyethers.

Also herein, the recitations of numerical ranges by endpoints includeall numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2,2.75, 3, 3.80, 4, 5, etc.). Furthermore, disclosure of a range includesdisclosure of all subranges included within the broader range (e.g., 1to 5 discloses 1 to 4, 1.5 to 4.5, 4 to 5, etc.).

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In one aspect, the present invention provides a coating composition thatincludes a polymer, more preferably a binder polymer, and even morepreferably a polyether binder polymer. Although the ensuing discussionfocuses primarily on coating end uses, it is contemplated that thepolymer of the present invention, as well as intermediates thereof mayhave utility in a variety of other end uses such as, for example, inadhesives or composites.

Coating compositions of the present invention preferably include atleast a film-forming amount of the polymer described herein. In additionto the polymer, the coating composition may also include one or moreadditional ingredients such as, for example, a crosslinker, a liquidcarrier, and any other suitable optional additives. Although anysuitable cure mechanism may be used, thermoset coating compositions arepreferred. Moreover, although coating compositions including a liquidcarrier are presently preferred, it is contemplated that the polymer ofthe present invention may have utility in solid coating applicationtechniques such as, for example, powder coating.

Coating compositions of the present invention may have utility in avariety of end uses, including packaging coating end uses. Other coatingend uses may include industrial coatings, marine coatings (e.g., forship hulls), storage tanks (e.g., metal or concrete), architecturalcoatings (e.g., on cladding, metal roofing, ceilings, garage doors,etc.), gardening tools and equipment, toys, automotive coatings, metalfurniture coatings, coil coatings for household appliances, floorcoatings, and the like.

Preferred coating compositions of the present invention exhibit asuperior combination of coating attributes such as good flexibility,good substrate adhesion, good chemical resistance and corrosionprotection, good fabrication properties, and a smooth and regularcoating appearance free of blisters and other application-relateddefects.

In preferred embodiments, the coating composition is suitable for use asan adherent packaging coating and, more preferably, as an adherentcoating on an interior and/or exterior surface of a food or beveragecontainer. Thus, in preferred embodiments, the coating composition issuitable for use as a food-contact coating. It is also contemplated thatthe coating composition may have utility in cosmetic packaging ormedical packaging coating end uses, and as a drug-contact coating inparticular (e.g., as an interior coating of a metered dose inhalercan—commonly referred to as an “MDI” container). It is also contemplatedthat the coating composition may have utility in coating applications inwhich the coated substrate will contact bodily fluids such as, e.g., asan interior coating of a blood vial.

The ingredients used to make the polymer of the present invention arepreferably free of any dihydric phenols, or corresponding diepoxides(e.g., diglycidyl ethers), that exhibit an estrogenic agonist activityin the MCF-7 assay (discussed later herein) greater than or equal tothat that exhibited by 4,4′-(propane-2,2-diyl)diphenol in the assay.More preferably, the aforementioned ingredients are free of any dihydricphenols, or corresponding diepoxides, that exhibit an estrogenic agonistactivity in the MCF-7 assay greater than or equal to that of bisphenolS. Even more preferably, the aforementioned ingredients are free of anydihydric phenols, or corresponding diepoxides, that exhibit anestrogenic agonist activity in the MCF-7 assay greater than that of4,4′-(propane-2,2-diyl)bis(2,6-dibromophenol). Optimally, theaforementioned ingredients are free of any dihydric phenols, orcorresponding diepoxides, that exhibit an estrogenic agonist activity inthe MCF-7 assay greater than about that of2,2-bis(4-hydroxyphenyl)propanoic acid. The same is preferably true forany other ingredients of a coating composition including the polymer.

While not intending to be bound by any theory, it is believed that adihydric phenol is less likely to exhibit any appreciable estrogenicagonist activity if the compound's chemical structure is sufficientlydifferent from compounds having estrogenic activity such asdiethylstilbestrol. The structure of preferred dihydric phenolcompounds, as will be discussed herein, are sufficiently different suchthat the compounds do not bind and activate a human receptor. Thesepreferred compounds are, in some instances, at least about 6 or more,orders of magnitude less active than diethylstilbestrol (e.g., whenassessing estrogenic agonist effect using an in vitro assay such as theMCF-7 cell proliferation assay discussed later herein). Without beingbound by theory, it is believed that such desirable structuraldissimilarity can be introduced via one or more structural features,including any suitable combination thereof. For example, it is believedthat one or more of the following structural characteristics can be usedto achieve such structural dissimilarity:

-   -   segments of Formula IB    -   steric hindrance (e.g., relative to one or more hydroxyl        phenols),    -   molecular weight that is arranged in three-dimensional space        such that: (i) the compound does not fit, or does not readily        fit, in the active site of a human estrogen receptor or (ii) the        structural configuration interferes with activation of the human        estrogen receptor once inside the active site, and    -   the presence of polar groups (e.g., in addition to the two        hydroxyl groups of a bisphenol compound).

In one preferred embodiment, the polymer of the present invention, whichis preferably a polyether polymer, includes one or more segments of thebelow Formula (I), and more preferably a plurality of such segments.

wherein:

-   -   each of the pair of oxygen atoms depicted in Formula (I) is        preferably present in an ether or ester linkage, more preferably        an ether linkage;    -   H denotes a hydrogen atom, if present;    -   each R¹ is preferably independently an atom or group preferably        having at atomic weight of at least 15 Daltons that is        preferably substantially non-reactive with an epoxy group;    -   v is independently 0 to 4, more preferably 1 to 4, even more        preferably 2 to 4;    -   w is 4;    -   when v is 1 to 4, each of the phenylene groups depicted in        Formula (I) preferably includes at least one R¹ attached to the        ring preferably at an ortho or meta position relative to the        oxygen atom;    -   R², if present, is preferably a divalent group;    -   n is 0 or 1, with the proviso that if n is 0, the phenylene        groups depicted in Formula (I) can optionally join to form a        fused ring system (e.g., a substituted naphthalene group) in        which case w is 3 (as opposed to 4) and v is 0 to 3 (as opposed        to 3);    -   t is or 1; and    -   two or more R¹ and/or R² groups can optionally join to form one        or more cyclic groups.

When t is 1, the segment of Formula (I) is a segment of the belowFormula (IA).

When t is 0, the segment of Formula (I) is a segment of the belowFormula (IB).

As depicted in the above Formula (I), the segment includes at least onephenylene group when t is 0 (illustrated in Formula (IB)) and includesat least two phenylene groups when t is 1 (illustrated in Formula (IA)).The segments of each of Formulas (IA) and (IB) may optionally includeone or more additional phenylene or other aryl or heteroaryl groups inaddition to those depicted. Although aryl groups having a six-carbonaromatic ring are presently preferred, it is contemplated that any othersuitable aryl or heteroaryl groups may be used in place of the phenylenegroups depicted in Formula (I). As depicted in the above Formula (I),the substituent groups (e.g., —O—, H, R¹, and R²) of each phenylenegroup can be located at any position on the ring relative to oneanother, although in certain preferred embodiments at least one R¹ ispositioned on the ring immediately adjacent to the oxygen atom. In otherembodiments in which other aryl or heteroarylene group(s) are used inplace of the depicted phenylene group(s) in Formula (I), it iscontemplated that the same would hold true for the substituent groups ofsuch other aryl or heteroarylene group(s).

In preferred embodiments, each R¹ and R², if present, are preferably notreactive with an oxirane group at a temperature of less than about 200°C.

In certain preferred embodiments, v is 1 or more and R¹ is preferablylocated at an ortho position on the ring relative to the oxygen atom. Insome embodiments, an R¹ is located at each ortho position on the ringrelative to the oxygen atom. While not intending to be bound by anytheory, it is believed that the positioning of one or more R¹ groups atan ortho position relative to the oxygen atom depicted in Formula (I)may be beneficial in reducing or eliminating estrogenic agonistactivity. The benefits of R¹ with regards to an absence of appreciableestrogenic activity in certain such potential migrants are discussed ingreater detail below.

In another embodiment, the one or more hydroxyl groups present on eacharyl ring of a polyhydric phenol compound (typically phenol hydroxylgroups of a dihydric phenol) are sterically hindered by one or moreother substituents of the aryl ring, as compared to a similar polyhydricphenol compound having hydrogen atoms present at each ortho and/or metaposition. It is believed that it may be preferable to have substituentgroups positioned at each ortho position relative to the aforementionedhydroxyl groups to provide optimal steric effect. It is believed thatthe steric hindrance can prevent or limit the ability of a polyhydricphenol compound, and particularly a polyhydric phenol compound havingtwo or more phenylene rings with hydroxyl groups, to act as an agonistfor a human estrogen receptor.

Preferred R¹ groups are sufficiently “bulky” to provide a suitable levelof steric hindrance for the aforementioned hydroxyl groups to achievethe desired effect. To avoid any ambiguity, the term “group” when usedin the context of R¹ groups refers to both single atoms (e.g., a halogenatom) or molecules (i.e., two or more atoms). The optimal chemicalconstituents, size, and/or configuration (e.g., linear, branched, etc.)of the one or more R¹ groups may depend on a variety of factors,including, for example, the location of the R¹ group on the aryl group.

Certain Preferred segments of Formula (I) include up to four R¹ groupshaving an atomic weight of at least 15 Daltons. In some embodiments, thesegments of Formula (I) include up to four R¹ groups having an atomicweight of at least 25, at least 40, or at least 50 Daltons. While themaximum suitable size of R¹ is not particularly limited, typically itwill be less than 500 Daltons, more typically less than 100 Daltons, andeven more typically less than 60 Daltons. Non-limiting examples of R¹groups include groups having at least one carbon atom (e.g., organicgroups), halogen atoms, sulfur-containing groups, or any other suitablegroup that is preferably substantially non-reactive with an epoxy group.

In presently preferred embodiments, the R¹ groups of each phenylenegroup, if present, preferably includes at least one carbon atom, morepreferably 1 to 10 carbon atoms, and even more preferably 1 to 4 carbonatoms. R¹ will typically be a saturated or unsaturated hydrocarbongroup, more typically saturated, that may optionally include one or moreheteroatoms other than carbon or hydrogen atoms (e.g., N, O, S, Si, ahalogen atom, etc.). Examples of suitable hydrocarbon groups may includesubstituted or unsubstituted: alkyl groups (e.g., methyl, ethyl, propyl,butyl, etc., including isomers thereof), alkenyl groups, alkynyl groups,alicyclic groups, aryl groups, or combinations thereof.

In certain preferred embodiments, each phenylene group depicted inFormula (I) includes at least one alkyl R¹ group. As discussed above,any suitable isomer may be used. Thus, for example, a linear butyl groupmay be used or a branched isomer such as an isobutyl group or atert-butyl group. In one embodiment, a tert-butyl group (and morepreferably a tert-butyl moiety) is a preferred R¹ group.

As previously mentioned, it is contemplated that R¹ may include one ormore cyclic groups. In addition, R¹ may form a cyclic or polycyclicgroup with one or more other R¹ groups and/or R².

In some embodiments, one or both phenylene groups depicted in Formula(I) includes an R¹ located ortho to the oxygen that is a halogen atom,more preferably a higher molecular weight halogen such as bromine oriodine. However, in preferred embodiments, the segment of Formula (I)does not include any halogen atoms. Moreover, in presently preferredembodiments, the polymer including one or more segments of Formula (I)is preferably free of halogen atoms.

In some embodiments, a suitable R¹ is selected and positioned at theortho position such that a width “f” measured perpendicular from acenter-line of the phenylene group (or other suitable aryl group) to themaximal outside extent of the van der Waals volume of R¹ (correspondingto the radius of the van der Waals radius of R¹) is greater than about4.5 Angstroms. This width measurement may be determined via theoreticalcalculation using suitable molecular modeling software and isillustrated below.

As illustrated above, the centerline for the depicted phenylene groupincludes the carbon atom to which the phenol hydroxyl group attaches andthe para carbon atom. For example, while not intending to be bound byany theory, it is believed that it is generally desirable that f begreater than about 4.5 Angstroms if R² is a —C(CH₃)₂— group. In someembodiments, R¹ may be selected and positioned at an ortho position suchthat f is less than about 4.5 Angstroms. For example, if R² is amethylene bridge (—CH₂—), in some embodiments, R¹ can be selected andpositioned such that f is less than about 4.5 Angstroms, which isbelieved to be the case for certain preferred segments of Formula (I)derived from, e.g., 4,4′-methylenebis(2,6-dimethylphenol).

R² is present or absent in the segment of Formula (IA) depending onwhether n is 0 or 1. When R² is absent in the segment of Formula (IA),either (i) a carbon atom of one phenylene ring is covalently attached toa carbon atom of the other phenylene ring (which occurs when w is 4) or(ii) the phenylene groups depicted in Formula (IA) join to form a fusedring system (which occurs when w is 3 and the two phenylene groups areso fused). In some embodiments, R² (or the ring-ring covalent linkage ifR² is absent) is preferably attached to at least one, and morepreferably both, phenylene rings at a para position (i.e., 1,4 position)relative to the oxygen atom depicted in Formula (IA). An embodiment ofthe segment of Formula (IA), in which n is 0, w is 3, and v isindependently 0 to 3 such that the two phenylene groups have joined toform a naphthalene group, is depicted below.

R² can be any suitable divalent group including, for example,carbon-containing groups (which may optionally include heteroatoms suchas, e.g., N, O, P, S, Si, a halogen atom, etc.), sulfur-containinggroups (including, e.g., a sulfur atom, a sulfinyl group (—(S(O)—), asulfonyl group (—S(O₂)—), etc.), oxygen-containing groups (including,e.g., an oxygen atom, a ketone group, etc.), nitrogen-containing groups,or a combination thereof.

In preferred embodiments of the segment of Formula (IA), R² is presentand is typically an organic group containing less than about 15 carbonatoms, and even more typically an organic group containing 1 or 4-15carbon atoms. In some embodiments, R² includes 8 or more carbon atoms.R² will typically be a saturated or unsaturated hydrocarbon group, moretypically a saturated divalent alkyl group, and most preferably an alkylgroup that doesn't constrain the movement of the connected phenylenegroups in an orientation similar to that of diethylstilbestrol ordienestrol. In some embodiments, R² may include one or more cyclicgroups, which may be aromatic or alicyclic and can optionally includeheteroatoms. The one or more optional cyclic groups of R² can bepresent, for example, (i) in a chain connecting the two phenylene groupsdepicted in Formula (IA), (ii) in a pendant group attached to a chainconnecting the two phenylene groups, or both (i) and (ii).

The atomic weight of the R² group, if present, may be any suitableatomic weight. Typically, however, R² has an atomic weight of less thanabout 500 Daltons, less than about 400 Daltons, less than 300 Daltons,or less than 250 Daltons.

In some embodiments, R² includes a carbon atom that is attached to acarbon atom of each of the phenylene groups depicted in Formula (I). Forexample, R² can have a structure of the formula —C(R⁷)(R⁸)—, wherein R⁷and R⁸ are each independently a hydrogen atom, a halogen atom, anorganic group, a sulfur-containing group, a nitrogen-containing group,or any other suitable group that is preferably substantiallynon-reactive with an epoxy group, and wherein R⁷ and R⁸ can optionallyjoin to form a cyclic group. In some embodiments, at least one of R⁷ andR⁵ is a hydrogen atom, and more preferably both. In one preferredembodiment, R² is a divalent methylene group (—CH₂—). While notintending to be bound by theory, it is believed that it may be generallydesirable to avoid using an R² group wherein each of R⁷ and R⁸ aremethyl (—CH₃) groups. It may also be generally desirable to avoid usingan R² group in which R⁷ and R⁸ join to form a monocyclic cyclohexylgroup.

It is also thought to be generally desirable to avoid using either ofthe following “constrained” unsaturated structures (i) or (ii) as R²:(i) —C(R⁹)═C(R⁹)— or (ii) —C(═C(R¹⁰)_(y))—C(═C(R¹⁰)_(y))—, wherein y is1 or 2 and each of R⁹ or R¹⁰ is independently a hydrogen atom, a halogenatom, an organic group, or a monovalent group. For example, thefollowing unsaturated structures (i) and (ii) are preferably avoided asR²: (i) —C(CH₂CH₃)═C(CH₂CH₃)— and (ii) —C(═CHCH₃)—C(═CHCH₃)—.

While not intending to be bound by theory it is believed that a suitablylow atomic weight R² group such as, e.g., —CH₂— (14 Daltons), can helpavoid estrogenic activity. In some embodiments where R² is a —C(R⁷)(R⁸)—group, it may be desirable that R² have an atomic weight of less than 42Daltons or less than 28 Daltons. It is also believed that a suitablyhigh atomic weight R² can also help interfere with the ability of adihydric phenol to function as an agonist for a human estrogen receptor.In some embodiments where R² is a —C(R⁷)(R⁸)— group, it may be desirablethat R² have an atomic weight that is greater than about: 125, 150, 175,or 200 Daltons. By way of example, a dihydric phenol compound has beendetermined to be appreciably non-estrogenic that: (a) is not “hindered”(the phenol hydroxyl groups are not surrounded by ortho hydrogens) and(b) has an R² group in the form of —C(R⁷)(R⁸)— having an atomic weightgreater than 200 Daltons.

While not intending to be bound to theory, preferred R²'s includedivalent groups that promote that the orientation of a dihydric phenolcompound in a three-dimensional configuration that is sufficientlydifferent from 17β-estradiol or other compounds (e.g.,diethylstilbestrol) having estrogenic activity. For example, while notintending to be bound to theory, it is believed that the presence of R²as an unsubstituted methylene bridge (—CH₂—) can contribute to thereduction or elimination of estrogenic activity. It is also contemplatedthat a singly substituted methylene bridge having one hydrogen attachedto the central carbon atom of the methylene bridge (—C(R⁷)(H)—; see,e.g. the R² group of 4,4′Butylidenebis(2-t-butyl-5-methylphenol)) mayalso contribute such a beneficial effect, albeit perhaps to a lesserextent.

In some embodiments, R² is of the formula —C(R⁷)(R⁸)— wherein R⁷ and R⁸form a ring together that includes one or more heteroatoms. In one suchembodiment, the ring formed by R⁷ and R⁸ further includes one or moreadditional cyclic group such as, e.g., one or more aryl cyclic groups(e.g., two phenylene rings).

In one embodiment, R² is of the formula —C(R⁷)(R⁸)— wherein at least oneof R⁷ and R⁸ form a ring with an R¹ of the depicted phenylene group. Inone such embodiment, each of R⁷ and R⁸ forms such a ring with adifferent depicted phenylene group.

In some embodiments, the segment of Formula (I) does not include anyester linkages in a backbone of R² connecting the pair of depictedphenylene groups. In some embodiments, the polymer of the presentinvention does not include any backbone ester linkages.

The oxygen atom of a phenylene ring(s) depicted in Formula (I) can bepositioned on the ring at any position relative to R² (or relative tothe other phenylene ring if R² is absent). In some embodiments, theoxygen atom (which is preferably an ether oxygen) and R² are located atpara positions relative to one another. In other embodiments, the oxygenatom and R² may be located ortho or meta to one another.

The segments of Formula (I) can be of any suitable size. Typically, thesegments of Formula (I) will have an atomic weight of less than 1,000,less than 600, or less than 400 Daltons. More typically, the segments ofFormula (I) will have an atomic weight of about 100 to about 400Daltons.

In preferred embodiments, the substituted phenylene groups of Formula(IA) are symmetric relative to one another. Stated otherwise, thesubstituted phenylene groups are preferably formed from the same phenolcompound, thereby resulting in the same substituent groups on each ringlocated at the same ring positions. An example of a compound havingsymmetric phenylene groups is provided below.

An example of a compound having phenylene groups that are not symmetricis provided below, in which a methyl group is at a meta position on onering and at an ortho position on the other.

In preferred embodiments, the polymer of the present invention includesa plurality of segments of Formula (I), which are preferably dispersedthroughout a backbone of the polymer, more preferably a polyetherbackbone. In preferred embodiments, the segments of Formula (I)constitute a substantial portion of the overall mass of the polymer.Typically, segments of Formula (I) constitute at least 10 weight percent(“wt-%”), preferably at least 30 wt-%, more preferably at least 40 wt-%,even more preferably at least 50 wt-%, and optimally at least 55 wt-% ofthe polymer.

The weight percent of segments of Formula (I) in the polymer of thepresent invention may be below the amounts recited above in certainsituations, and can even be substantially below. By way of example, theconcentration of segments of Formula (I) may be outside the rangesrecited above if the polymer of the present invention, which ispreferably a polyether polymer, includes large molecular weightadditional components such as may occur, for example, when the polymeris a copolymer such as an acrylic-containing copolymer (e.g., anacrylic-polyether copolymer formed by grafting acrylic onto a polyetherpolymer of the present invention). In such embodiments, the weightpercent of segments of Formula (I) present in the polymer is preferablyas described above (e.g., ≥10 wt-%, ≥30 wt-%, ≥40 wt-%, ≥50 wt-%, ≥55wt-%), based on the weight percent of segments of Formula (I) relativeto the total polyether fraction of the polymer (while not consideringthe total weight of non-polyether portions such as, for example, acrylicportions). In general, the total polyether fraction of the polymer canbe calculated based on the total weight of polyepoxide and polyhydricphenol reactants incorporated into the polymer.

Depending upon the particular embodiment, the polymer of the presentinvention is preferably amorphous or semi-crystalline.

The polymer can include branching, if desired. In preferred embodiments,however, the polymer of the invention is a linear or substantiallylinear polymer.

If desired, the backbone of the polymer may include step-growth linkages(e.g., condensation linkages) other than ether linkages (e.g., inaddition to, or in place of, the ether linkages) such as, for example,amide linkages, carbonate linkages, ester linkages, urea linkages,urethane linkages, etc. Thus, for example, in some embodiments, thebackbone may include both ester and ether linkages. In some embodiments,the backbone of the polymer does not include any condensation linkagesor other step-growth linkages other than ether linkages.

The polymer of the present invention preferably includes hydroxylgroups. In preferred embodiments, the polymer includes a plurality ofhydroxyl groups attached to the backbone. In preferred embodiments,polyether portions of the polymer backbone include secondary hydroxylgroups distributed throughout. Preferred secondary hydroxyl groups arepresent in —CH₂—CH(OH)—CH₂— or —CH₂—CH₂—CH(OH)— segments, which arepreferably derived from an oxirane group. Such segments may be formed,for example, via reaction of an oxirane group and a hydroxyl group(preferably a hydroxyl group of a polyhydric phenol). In someembodiments, CH₂—CH(OH)—CH₂— or CH₂—CH₂—CH(OH)— segments are attached toeach of the ether oxygen atoms of preferred segments of Formula (I).

The backbone of the polymer of the present invention may include anysuitable terminal groups, including, for example, epoxy and/or hydroxylgroups (e.g., a hydroxyl group attached to a terminal aryl or heteroarylring).

In preferred embodiments, the polymer of the present invention is formedusing reactants that include at least one polyepoxide compound, moretypically at least one diepoxide compound. Although any suitableingredients may be used to form the polymer, in presently preferredembodiments, the polymer is formed via reaction of ingredients thatinclude: (a) one or more polyepoxides, more preferably one or morediepoxides, and (b) one or more polyols, more preferably one or morepolyhydric phenols, and even more preferably one or more dihydricphenols. The polymer is preferably derived from ingredients including adiepoxide having one or more “hindered” aryl or heteroaryl groups, andmore preferably one or more “hindered” phenylene groups described herein(e.g., as depicted in Formula (I)).

While it is contemplated that the segments of Formula (I) may beincorporated into the polymer using ingredients other than a polyepoxidecompound, in preferred embodiments some, or all, of the segments ofFormula (I) are incorporated into the polymer using a polyepoxidecompound, and more preferably a diepoxide compound. The polyepoxidecompound may be upgraded by reaction with an extender (e.g., a diolwhich is preferably a polyhydric phenol) to form a binder polymer, morepreferably a polyether binder polymer, of a suitable molecular weightusing any suitable extender or combinations of extenders. As discussedabove, diols (e.g., polyhydric phenols, and dihydric phenols inparticular) are preferred extenders. Examples of other suitableextenders may include polyacids (and diacids in particular) or phenolcompounds having both a phenol hydroxyl group and a carboxylic group(e.g., para hydroxy benzoic acid and/or para hydroxy phenyl aceticacid). Conditions for such reactions are generally carried out usingstandard techniques that are known to one of skill in the art or thatare exemplified in the examples section.

The epoxy groups (also commonly referred to as “oxirane” groups) of thepolyepoxide compound may be attached to the compound via any suitablelinkage, including, for example, ether-containing or ester-containinglinkages. Glycidyl ethers of polyhydric phenols and glycidyl esters ofpolyhydric phenols are preferred polyepoxide compounds, with diglycidylethers being particularly preferred.

A preferred polyepoxide compound for use in incorporating segments ofFormula (I) into the polymer of the present invention is depicted in thebelow Formula (II):

wherein:

-   -   R¹, R², n, t, v, and w are as described above for Formula (I);    -   s is 0 to 1, more preferably 1;    -   R³, if present, is a divalent group, more preferably a divalent        organic group; and    -   preferably each R⁴ is independently a hydrogen atom, a halogen        atom, or a hydrocarbon group that may include one or more        heteroatoms; more preferably each R⁴ is a hydrogen atom.

When t is 1, the polyepoxide of Formula (II) is a segment of the belowFormula (IIA).

When t is 0, the polyepoxide of Formula (II) is a segment of the belowFormula (IIB).

R³ is typically a hydrocarbyl group, which may optionally include one ormore heteroatoms. Preferred hydrocarbyl groups include groups havingfrom one to four carbon atoms, with methylene groups being particularlypreferred. In some embodiments, R³ includes a carbonyl group. In onesuch embodiment, R³ includes a carbonyl group that is attached to theoxygen atom depicted in Formula (II) (e.g., as in an ester linkage).

In presently preferred embodiments, R⁴ is a hydrogen atom.

Preferred polyepoxide compounds of Formula (II) are non-mutagenic, morepreferably non-genotoxic. A useful test for assessing both mutagenicityand genotoxicity is the mammalian in vivo assay known as the in vivoalkaline single cell gel electrophoresis assay (referred to as the“comet” assay). The method is described in: Tice, R. R. “The single cellgel/comet assay: a microgel electrophoretic technique for the detectionof DNA damage and repair in individual cells.” EnvironmentalMutagenesis. Eds. Phillips, D. H and Venitt, S. Bios Scientific, Oxford,U D, 1995, pp. 315-339. A negative test result in the comet assayindicates that a compound is non-genotoxic and, therefore,non-mutagenic, though a positive test does not definitively indicate theopposite and in such cases a more definitive test may be utilized (e.g.,a two-year rat feeding study).

If t of Formula (II) is O, v is preferably 1 or more, more preferably 2or more. While not intending to be bound by any theory, it is believedthat the presence of one or more R¹ groups, and particularly one or moreortho R¹ groups, can contribute to the diepoxide of Formula (IIB) beingnon-genotoxic. By way of example, 2,5-di-tert-butylhydroquinone isnon-genotoxic.

In some embodiments, the polyepoxide compound of Formula (II) is formedvia epoxidation of a dihydric phenol compound (e.g., via a reactionusing epichlorohydrin or any other suitable material). Such a dihydricphenol compound is depicted in the below Formula (III), wherein R¹, R²,n, t, v, and w are as in Formula (I):

When t is 1, the compound of Formula (III) is of the below Formula(IIIA).

When t is 0, the compound of Formula (III) is of the below Formula(IIIB).

Preferred compounds of Formula (III) do not exhibit appreciableestrogenic activity. Preferred appreciably non-estrogenic compoundsexhibit a degree of estrogen agonist activity, in a competent in vitrohuman estrogen receptor assay, that is preferably less than thatexhibited by 4,4′-(propane-2,2-diyl)diphenol in the assay, even morepreferably less than that exhibited by bisphenol S in the assay, evenmore preferably less than that exhibited by4,4′-(propane-2,2-diyl)bis(2,6-dibromophenol) in the assay, andoptimally less than about that exhibited by2,2-bis(4-hydroxyphenyl)propanoic acid in the assay. It has been foundthat compounds such as 4,4′-methylenebis(2,6-di-t-butylphenol),2,2′-methylenebis(4-methyl-6-t-butylphenol),4,4′-methylenebis(2,6-dimethylphenol),4,4′butylidenebis(2-t-butyl-5-methylphenol), and2,5-di-t-butylhydroquinone do not exhibit appreciable estrogenicactivity in a suitable in vitro assay whose results are known to bedirectly correlated to the results of the MCF-7 cell proliferation assay(“MCF-7 assay”) through analysis of common reference compounds.

The MCF-7 assay is a useful test for assessing whether a polyhydricphenol compound is appreciably non-estrogenic. The MCF-7 assay usesMCF-7, clone WS8, cells to measure whether and to what extent asubstance induces cell proliferation via estrogen receptor (ER)-mediatedpathways. The method is described in “Test Method Nomination: MCF-7 CellProliferation Assay of Estrogenic Activity” submitted for validation byCertiChem, Inc. to the National Toxicology Program Interagency Centerfor the Evaluation of Alternative Toxicological Methods (NICEATM) onJan. 19, 2006 (available online athttp://iccvam.niehs.nih.gov/methods/endocrine/endodocs/SubmDoc.pdf).

A brief summary of the method of the aforementioned MCF-7 assay isprovided below. MCF-7, clone WS8, cells are maintained at 37° C. in RMPI(or Roswell Park Memorial Institute medium) containing Phenol Red (e.g.,GIBCO Catalog Number 11875119) and supplemented with the indicatedadditives for routine culture. An aliquot of cells maintained at 37° C.are grown for 2 days in phenol-free media containing 5% charcoalstripped fetal bovine serum in a 25 cm² tissue culture flask. Using arobotic dispenser such as an epMotion 5070 unit, MCF-7 cells are thenseeded at 400 cells per well in 0.2 ml of hormone-free culture medium inCorning 96-well plates. The cells are adapted for 3 days in thehormone-free culture medium prior to adding the chemical to be assayedfor estrogenic activity. The media containing the test chemical isreplaced daily for 6 days. At the end of the 7-day exposure to the testchemical, the media is removed, the wells are washed once with 0.2 ml ofHBSS (Hanks' Balanced Salt Solution), and then assayed to quantifyamounts of DNA per well using a micro-plate modification of the Burtondiphenylamine (DPA) assay, which is used to calculate the level of cellproliferation.

Examples of appreciably non-estrogenic polyhydric phenols includepolyhydric phenols that, when tested using the MCF-7 assay, exhibit aRelative Proliferative Effect (“RPE”) having a logarithmic value (withbase 10) of less than about −2.0, more preferably an RPE of −3 or less,and even more preferably an RPE of −4 or less. RPE is the ratio betweenthe EC50 of the test chemical and the EC50 of the control substance17-beta estradiol times 100, where EC50 is “effective concentration 50%”or half-maximum stimulation concentration for cell proliferationmeasured as total DNA in the MCF-7 assay.

Preferred polyether polymers of the present invention are substantiallyfree, more preferably completely free, of bound polyhydric phenols (andepoxides thereof) having an RPE of less than about −2.0. Morepreferably, the polyether polymer are free of bound polyhydric phenols(and epoxides thereof) having an RPE of −3 or less. Optimally, thepolyether polymer are free of bound polyhydric phenols (and epoxidesthereof) having an RPE of −3 or less.

A Table is provided below that includes some exemplary preferredpolyhydric compounds of Formula (III) and their expected or measuredlogarithmic RPE values in the MCF-7 assay. The structures of some of thecompounds included in the Table are provided following the Table, withthe number listed below each structure corresponding to that listed inthe Table.

Polyhydric Compound of Reference Formula (III) Structure Compound LogRPE 17β-estradiol 2.00 diethyl- about 2 stilbestrol dienestrol about 2Genistein −2 Bisphenol S (not preferred) −2 Bisphenol F (not preferred)−2 4,4′-isopropylidenebis(2,6-  1 −2 dimethylphenol)4,4′-(propane-2,2-diyl)bis(2,6- 16 −3 dibromophenol)4,4′-(ethane-1,2-diyl)bis(2,6-  2 −3 dimethylphenol)4,4′,4″-(ethane-1,1,1-  3 −3 triyl)triphenol 4,4′-(1-phenylethane-1,1- 4 −3 diyl)diphenol 2,2-bis(4-hydroxyphenyl)  5 less than −4 propanoicacid 4,4′-methylenebis(2,6-  6 less than −4 dimethylphenol)4,4′-butylidenebis(2-t-butyl-5-  7 less than −4 methylphenol)4,4′-methylenebis(2,6-di-t-  8 less than −4 butylphenel)2,2′-methylenebis(4-methyl-6-t-  9 less than −4 butylphenol4,4′-(1,4-phenylenebis(propane- 10 less than −4 2,2-diyl))diphenol2,2′methylenebis(phenol) 11 less than −4 2,5-di-t-butylhydroquinone 12less than −4 2,2′-Methylenebis(6-(1- 13 less than −4methylcyclohexyl)-4- methylphenol 2,2′-Methylenebis(6-t-butyl-4- 14 lessthan −4 methylphenol) 2,2′Methylenebis(4-ethyl-6-t- 15 less than −4butylphenol)

Compounds having no appreciable estrogenic activity may be beneficial inthe event that any unreacted, residual compound may be present in acured coating composition. While the balance of scientific data does notindicate that the presence in cured coatings of very small amounts ofresidual compounds having estrogenic activity in an in vitro recombinantcell assay pose a human health concern, the use of compounds having noappreciable estrogenic activity in such an assay may nonetheless bedesirable from a public perception standpoint. Thus, in preferredembodiments, the polymer of the present invention is preferably formedusing polyhydric phenol compounds that do not exhibit appreciableestrogenic activity in the MCF-7 assay.

While not intending to be bound by any theory, as previously discussed,it is believed that the presence of substituent groups (i.e., a groupother than a hydrogen atom) at one or more of the ortho and/or metapositions of each phenylene ring of the Formula (III) compound, relativeto the phenol hydroxyl group of each ring, can reduce or effectivelyeliminate any estrogenic activity. It is believed that theinhibition/elimination of estrogenic activity may be attributable to oneor more of the following: (a) steric hindrance of the phenol hydroxylgroup (which may cause the overall polyhydric phenol structure to besufficiently different from estrogenically active compounds such asdiethylstilbestrol), (b) the compound having an arranged molecularweight due to the presence of the one or more substituent groups, (c)the presence of polar groups and/or (d) ortho hydroxyl groups relativeto R². Substitution at one or both of the ortho positions of eachphenylene ring is presently preferred for certain embodiments as it isbelieved that ortho substitution can provide the greatest sterichindrance for the hydroxyl group.

As previously discussed, structural features other than the presence ofsuitable R¹ groups (e.g., features such as (b), (c), and (d) of thepreceding paragraph) are believed to inhibit/eliminate estrogenicactivity, even in the absence of any R¹ groups.

It is believed that molecular weight may be a structural characteristicpertinent to whether a polyhydric phenol is appreciably non-estrogenic.For example, while not intending to be bound by any theory, it isbelieved that if a sufficient amount of relatively “densely” packedmolecular weight is present in a polyhydric phenol, it can prevent thecompound from being able to fit into the active site of an estrogenreceptor (irrespective of whether the polyhydric phenol includes anyortho or meta R¹ groups). In some embodiments, it may be beneficial toform a polyether polymer from one or more polyhydric phenols (whether“hindered” or not) that includes at least the following number of carbonatoms: 20, 21, 22, 23, 24, 25, or 26 carbon atoms. In one suchembodiment, a polyhydric phenol of Formula (II) is used to make thepolyether polymer, where (a) v is independently 0 to 4 and (b) R² is ofthe formula —C(R⁷)(R⁸)— and includes at least 8, at least 10, at least12, or at least 14 carbon atoms (or otherwise has an R² of sufficientlyhigh atomic weight to prevent the compound from fitting into the activesite).

The presence of one or more polar groups on the polyhydric phenolcompounds of Formula (III) may be beneficial in certain embodiments,particularly for certain embodiment of Formula (IIIA). The polar groupsmay be located at any suitable location of the compounds of Formula(II), including in R¹ or R². Suitable polar groups may include ketone,carboxyl, carbonate, hydroxyl, phosphate, sulfoxide, and the like, anyother polar groups disclosed herein, and combinations thereof.

The below compounds of Formula (I) may also be used in certainembodiments if desired.

The below compounds are not presently preferred, but may be used incertain embodiments, if desired.

Additional polyhydric phenol compounds that may have utility inproducing the polymer of the present invention are provided below. Whilethe dihydric phenol structures listed below are not “hindered” in thesense of having bulky substituent groups at one or more ortho or metapositions of the phenylene ring(s), it is contemplated that each of thebelow dihydric phenol structures may be used in place of, or in additionto, the compounds of Formula (III). Such compounds are believed to beappreciably non-estrogenic for one or more of the reasons previouslydescribed herein.

Dihydric phenol compounds of Formula (III) can be converted to adiepoxide using any suitable process and materials. The use ofepichlorohydrin in the epoxidation process is presently preferred. Byway of example, below is a diepoxide formed via an epichlorohydrinepoxidation of 4,4′-methylenebis(2,6-di-t-butylphenol).

Numerous diepoxides have been successfully generated using variousdihydric phenol compounds of Formula (III), and polyether polymers havebeen successfully produced therefrom. In general, it is much moredifficult to successfully form a polyether polymer (using reasonableprocess times and conditions) using, as a dihydric phenol component, acompound of Formula (III) substituted at the ortho ring positions. Forexample, the inventors have found it difficult using conventionalindustrial processes to efficiently react4,4′-methylenebis(2,6-di-t-butylphenol) with diepoxide monomer to form apolyether polymer. (Somewhat surprisingly, however, dihydric phenolcompounds such as 4,4′-methylenebis(2,6-di-t-butylphenol) can undergo acondensation reaction with epichlorohydrin to form a diepoxide that isreactive with conventional dihydric phenols that are not substituted atthe ortho or meta positions.) While not wishing to be bound by theory,it is believed that the hydroxyl groups of such dihydric phenolcompounds are generally not sufficiently accessible to efficiently reactwith an oxirane group of a diepoxide monomer and form an ether linkage.Nonetheless, it is contemplated that a “hindered” dihydric phenolcompound of Formula (III) may be selected such that the hydroxyl groupsare sufficiently sterically hindered so that the compound does notexhibit appreciable estrogenic activity, while the hydroxyl groups arestill sufficiently accessible so that the compound can react with adiepoxide and build molecular weight under reasonable process times andconditions (e.g., less than 24 hours of reaction time at a reactiontemperature of less than about 240° C.).

In certain preferred embodiments, the dihydric phenol compound ofFormula (III) is substituted at one or both ortho ring positions of eachdepicted phenylene group with an R¹ group that includes from 1 to 4carbon atoms, more preferably from 1 to 3 carbon atoms, and even morepreferably 1 to 2 carbon atoms. In some embodiments, methyl groups arepreferred ortho R¹ groups, with the methyl moiety (i.e., —CH₃) beingparticularly preferred. While not intending to be bound by any theory,it has been observed that the presence of large ortho substituent groupscan sometimes affect the efficiency by which certain dihydric phenolcompounds of Formula (HI) are converted into diepoxides usingepichlorhydrin and, moreover, the efficiency by which the resultingdiepoxide can be upgraded into a polyether polymer having segments ofFormula (I).

The term “upgrade dihydric phenol” is used hereinafter to refer to apolyhydric phenol capable of participating in a reaction with thepolyepoxide of Formula (II) to build molecular weight and preferablyform a polymer. Any suitable upgrade polyhydric phenol may be used informing a polymer of the present invention. However, the use ofbisphenol A is not preferred. Preferred upgrade dihydric phenols arefree of bisphenol A and preferably do not exhibit appreciable estrogenicactivity.

Examples of suitable upgrade dihydric phenols for use in forming thepolyether polymer include any of the compounds of Formula (III), withcompounds of Formula (III) in which the hydroxyl group are unhindered byadjacent R groups being generally preferred for purposes of reactionefficiency. Some specific examples of suitable upgrade dihydric phenolsinclude hydroquinone, catechol, p-tert-butyl catechol, resorcinol,substituted variants thereof, or a mixture thereof. Hydroquinone is apresently preferred compound.

In some embodiments, the upgrade dihydric phenol is a compound ofFormula (III) and includes an R² group having one or more cyclic groups(e.g., alicyclic and/or aromatic groups), which may be monocyclic orpolycyclic groups (e.g., a divalent: norbornane, norbornene,tricyclodecane, bicyclo[4.4.0] decane, or isosorbide group, or acombination thereof). In some embodiments, R² of the upgrade dihydricphenol includes one or more ester linkages. For example, in someembodiments, R² is a —R⁶ _(w)—Z—R⁵—Z—R⁶ _(w)— segment, where: R⁵ is adivalent organic group; each R⁶, if present, is independently a divalentorganic group; each Z is independently an ester linkage that can be ofeither directionality (e.g., —C(O)—O— or —O—C(O)—; and each w isindependently 0 or 1. In one such embodiment, R⁵ includes at least onedivalent cyclic group such as, for example, a divalent polycyclic group,a divalent aryl or heteroarylene group (e.g., a substituted orunsubstituted phenylene group) or a divalent alicyclic group (e.g., asubstituted or unsubstituted cyclohexane or cyclohexene group). In oneembodiment, R² is —R⁶ _(w)—C(O)—O—R⁵—O—C(O)—R⁶ _(w)—. A furtherdiscussion of suitable segments containing ester linkages and materialsfor incorporating such segments into the polymer of the invention isprovided in U.S. Published Application No. 2007/0087146 by Evans et. al.and Published International Application No. WO 2011/130671 by Niederstet al.

By way of example, an upgrade dihydric phenol having acyclic-group-containing R² may be formed by reacting (a) a suitableamount (e.g., about 2 moles) of a Compound A having a phenol hydroxylgroup and a carboxylic acid or other active hydrogen group with (b) asuitable amount (e.g., about 1 mole) of a di-functional or higherCompound B having one or more cyclic groups (monocyclic and/orpolycyclic) and two or more active hydrogen groups capable of reactingwith the active hydrogen group of Compound A. Examples of preferredCompounds A include 4-hydroxy phenyl acetic acid, 3-hydroxybenzoic acid,4-hydroxybenzoic acid, and derivatives or mixtures thereof. Examples ofpreferred Compounds B include cyclic-containing diols such ascyclohexane dimethanol (CHDM); tricyclodecane dimethanol (TCDM);2,2,4,4-Tetramethyl-1,3-cyclobutanediol; a polycyclic anyhydrosugar suchas isosorbide, isomannide, or isoidide; and derivatives or mixturesthereof. In some embodiments, the cyclic group may be formed afterreaction of Compounds A and B. For example, a Diels-Alder reaction(using, e.g., cyclopentadiene as a reactant) could be used toincorporate an unsaturated bicyclic group such as a norbomene group intoCompound B, in which case Compound B in its unreacted form would need toinclude at least one non-aromatic carbon-carbon double bond in order toparticipate in the Diels-Alder reaction. For further discussion ofsuitable materials and techniques relating to such Diels-Alder reactionssee, for example, Published International App. Nos. WO 2010/118356 bySkillman et al. and WO 2010/118349 by Hayes et al.

Some examples of cyclic-group-containing and ester-link-containingupgrade dihydric phenol compounds are provided below. These compoundsare discussed in further detail in the previously referenced PublishedInternational Application No. WO 2011/130671 by Niederst et al.

It is also contemplated that the polymer of the present invention may beformed via reaction of ingredients including the dihydric phenolcompound of Formula (III) and a diepoxide other than that of Formula(II). Examples of such compounds include compounds such as1,4-cyclohexanedimethanol diglycidyl ether (CHDMDGE), neopentyl glycoldiglycidyl ether, 2-methy-1,3-propanediol diglycidyl ether,tricyclodecane dimethanol diglycidyl ether, and combinations thereof.While not intending to be bound by any theory, some such aliphaticdiepoxides (e.g., CHDMDGE and neopentyl glycol diglycidyl ether) thattend to yield polymers having lower Tg values may not be suitable forcertain interior packaging coating applications in which a relativelyhigh Tg polymer is desirable for purposes of corrosion resistance,although they may be suitable for exterior packaging coatingapplications or other end uses.

If desired, one or more comonomers and/or co-oligomers may be includedin the reactants used to generate the polymer of the present invention.Non-limiting examples of such materials include adipic acid, azelaicacid, terephthalic acid, isophthalic acid, and combinations thereof. Thecomonomers and/or cooligomers may be included in an initial reactionmixture of polyepoxide and polyhydric phenol and/or may be post-reactedwith the resulting polyether oligomer or polymer. In presently preferredembodiments, a comonomer and/or co-oligomer is not utilized to produce apolyether polymer of the present invention.

Preferred polymers of the present invention may be made in a variety ofmolecular weights. Preferred polyether polymers of the present inventionhave a number average molecular weight (Mn) of at least 2,000, morepreferably at least 3,000, and even more preferably at least 4,000. Themolecular weight of the polyether polymer may be as high as is neededfor the desired application. Typically, however, the Mn of the polyetherpolymer, when adapted for use in a liquid coating composition, will notexceed about 11,000. In some embodiments, the polyether polymer has anMn of about 5,000 to about 8,000. In embodiments where the polymer ofthe present invention is a copolymer, such as for example apolyether-acrylic copolymer, the molecular weight of the overall polymermay be higher than that recited above, although the molecular weight ofthe polyether polymer portion will typically be as described above.Typically, however, such copolymers will have an Mn of less than about20,000.

The polymer of the present invention may exhibit any suitablepolydispersity index (PDI). In embodiments in which the polymer is apolyether polymer intended for use as a binder polymer of a liquidapplied packaging coating (e.g., a food or beverage can coating), thepolyether polymer will typically exhibit a PDI of from about 1.5 to 5,more typically from about 2 to 3.5, and in some instances from about 2.2to 3 or about 2.4 to 2.8.

Advancement of the molecular weight of the polymer may be enhanced bythe use of a catalyst in the reaction of a diepoxide with one or moreupgrade comonomers such as, e.g., a polyhydric phenol of Formula (IV).Typical catalysts usable in the advancement of the molecular weight ofthe epoxy material of the present invention include amines, hydroxides(e.g., potassium hydroxide), phosphonium salts, and the like. Apresently preferred catalyst is a phosphonium salt catalyst. Thephosphonium catalyst useful in the present invention is preferablypresent in an amount sufficient to facilitate the desired condensationreaction.

Alternatively, epoxy-terminated polymers of the present invention may bereacted with fatty acids to form polymers having unsaturated (e.g., airoxidizable) reactive groups, or with acrylic acid or methacrylic acid toform free-radically curable polymers.

Advancement of the molecular weight of the polymer may also be enhancedby the reaction of a hydroxyl- or epoxy-terminated polymer of thepresent invention with a suitable diacid (such as adipic acid).

As discussed above, in certain preferred embodiments, the coatingcomposition of the present invention is suitable for use in forming afood-contact packaging coating. In order to exhibit a suitable balanceof coating properties for use as a food-contact packaging coating,including suitable corrosion resistance when in prolonged contact withpackaged food or beverage products which may be of a corrosive nature,the polymer of the present invention preferably has a glass transitiontemperature (“Tg”) of at least 60° C., more preferably at least 70° C.,and even more preferably at least 80° C. In preferred embodiments, theTg is less than 150° C., more preferably less than 130° C., and evenmore preferably less than 110° C. Tg can be measured via differentialscanning calorimetry (“DSC”) using the methodology disclosed in the TestMethods section. In preferred embodiments, the polymer is a polyetherpolymer exhibiting a Tg pursuant to the aforementioned Tg values.

While not intending to be bound by any theory, it is believed that it isimportant that the polymer exhibit a Tg such as that described above inapplications where the coating composition will be in contact with foodor beverage products during retort processing at high temperature (e.g.,at temperatures at or above about 100° C. and sometimes accompanied bypressures in excess of atmospheric pressure), and particularly whenretort processing food or beverage products that are more chemicallyaggressive in nature. It is contemplated that, in some embodiments, suchas, for example, where the coating composition is intended for use as anexterior varnish on a food or beverage container, the Tg of the polymermay be less than that described above (e.g., as low as about 30° C.) andthe coating composition may still exhibit a suitable balance ofproperties in the end use.

When the Tg of a polymer is referenced herein in the context of acoating composition including the polymer or a coated article coatedwith such a coating composition, the indicated Tg value for the polymerrefers to the Tg of the polymer prior to any cure of a coatingcomposition including the polymer.

While not intending to be bound by any theory, it is believed that theinclusion of a sufficient number of aryl and/or heteroaryl groups(typically phenylene groups) in the binder polymer of the presentinvention is an important factor for achieving suitable coatingperformance for food-contact packaging coatings, especially when theproduct to be packaged is a so called “hard-to-hold” food or beverageproduct. Sauerkraut is an example of a hard-to-hold product. Inpreferred embodiments, aryl and/or heteroaryl groups constitute at least25 wt-%, more preferably at least 30 wt-%, even more preferably at least35 wt-%, and optimally at least 45 wt-% of the polyether polymer, basedon the total weight of aryl and heteroaryl groups in the polymerrelative to the weight of the polyether polymer. The upper concentrationof aryl/heteroaryl groups is not particularly limited, but preferablythe amount of such groups is configured such that the Tg of thepolyether polymer is within the Tg ranges previously discussed. Thetotal amount of aryl and/or heteroaryl groups in the polyether polymerwill typically constitute less than about 80 wt-%, more preferably lessthan 75 wt-%, even more preferably less than about 70 wt-%, andoptimally less than 60 wt-% of the polyether polymer. The total amountof aryl and/or heteroaryl groups in the polyether polymer can bedetermined based on the weight of aryl- or heteroaryl-containing monomerincorporated into the polyether polymer and the weight fraction of suchmonomer that constitutes aryl or heteroaryl groups. In embodiments wherethe polymer is a polyether copolymer (e.g., a polyether-acryliccopolymer), the weight fraction of aryl or heteroaryl groups in thepolyether polymer portion(s) of the copolymer will generally be asdescribed above, although the weight fraction relative to the totalweight of the copolymer may be less.

Preferred aryl or heteroaryl groups include less than 20 carbon atoms,more preferably less than 11 carbon atoms, and even more preferably lessthan 8 carbon atoms. The aryl or heteroaryl groups preferably have atleast 4 carbon atoms, more preferably at least 5 carbon atoms, and evenmore preferably at least 6 carbon atoms. Substituted or unsubstitutedphenylene groups are preferred aryl or heteroaryl groups. Thus, inpreferred embodiments, the polyether fraction of the polymer includes anamount of phenylene groups pursuant to the amounts recited above.

In one embodiment, the polymer of the present invention does not includeany structural units derived from hydrogenated bisphenol A or adiepoxide of hydrogenated bisphenol A.

The polymers of the present invention can be applied to a substrate aspart of a coating composition that includes a liquid carrier. The liquidcarrier may be water, organic solvent, or mixtures of various suchliquid carriers. Accordingly, liquid coating compositions of the presentinvention may be either water-based or solvent-based systems. Examplesof suitable organic solvents include glycol ethers, alcohols, aromaticor aliphatic hydrocarbons, dibasic esters, ketones, esters, and thelike, and combinations thereof. Preferably, such carriers are selectedto provide a dispersion or solution of the polymer for furtherformulation.

It is expected that a polyether polymer of the present invention may besubstituted for any conventional epoxy polymer present in a packagingcoating composition known in the art. Thus, for example, the polyetherpolymer of the present invention may be substituted, for example, for aBPA/BADGE-containing polymer of an epoxy/acrylic latex coating system,for a BPA/BADGE-containing polymer of a solvent based epoxy coatingsystem, etc. The amount of binder polymer of the present inventionincluded in coating compositions may vary widely depending on a varietyof considerations such as, for example, the method of application, thepresence of other film-forming materials, whether the coatingcomposition is a water-based or solvent-based system, etc. Forliquid-based coating compositions, however, the binder polymer of thepresent invention will typically constitute at least 10 wt-%, moretypically at least 30 wt-%, and even more typically at least 50 wt-% ofthe coating composition, based on the total weight of resin solids inthe coating composition. For such liquid-based coating compositions, thebinder polymer will typically constitute less than about 90 wt-%, moretypically less than about 80 wt-%, and even more typically less thanabout 70 wt-% of the coating composition, based on the total weight ofresin solids in the coating composition.

In one embodiment, the coating composition is an organic solvent-basedcomposition preferably having at least 20 wt-% non-volatile components(“solids”), and more preferably at least 25 wt-% non-volatilecomponents. Such organic solvent-based compositions preferably have nogreater than 40 wt-% non-volatile components, and more preferably nogreater than 25 wt-% non-volatile components. For this embodiment, thenon-volatile film-forming components preferably include at least 50 wt-%of the polymer of the present invention, more preferably at least 55wt-% of the polymer, and even more preferably at least 60 wt-% of thepolymer. For this embodiment, the non-volatile film-forming componentspreferably include no greater than 95 wt-% of the polymer of the presentinvention, and more preferably no greater than 85 wt-% of the polymer.

In some embodiments, the coating composition of the present invention isa solvent-based system that includes no more than a de minimus amount ofwater (e.g., less than 2 wt-% of water), if any. One example of such acoating composition is a solvent-based coating composition that includesno more than a de minimus amount of water and includes: on a solidsbasis, from about 30 to 99 wt-%, more preferably from about 50 to 85wt-% of polyether polymer of the present invention; a suitable amount ofcrosslinker (e.g., a phenolic crosslinker or anhydride crosslinker); andoptionally inorganic filler (e.g., TiO₂) or other optional additives. Inone such solvent-based coating composition of the present invention, thepolyether polymer is a high molecular weight polyether polymer thatpreferably has an Mn of about 7,500 to about 10,500, more preferablyabout 8,000 to 10,000, and even more preferably about 8,500 to about9,500.

In one embodiment, the coating composition is a water-based compositionpreferably having at least 15 wt-% non-volatile components. In oneembodiment, the coating composition is a water-based compositionpreferably having no greater than 50 wt-% non-volatile components, andmore preferably no greater than 40 wt-% non-volatile components. Forthis embodiment, the non-volatile components preferably include at least5 wt-% of the polymer of the present invention, more preferably at least25 wt-% of the polymer, even more preferably at least 30 wt-% of thepolymer, and optimally at least 40 wt-% of the polymer. For thisembodiment, the non-volatile components preferably include no greaterthan 70 wt-% of the polymer of the present invention, and morepreferably no greater than 60 wt-% of the polymer.

If a water-based system is desired, techniques may be used such as thosedescribed in U.S. Pat. Nos. 3,943,187; 4,076,676; 4,247,439; 4,285,847;4,413,015; 4,446,258; 4,963,602; 5,296,525; 5,527,840; 5,830,952;5,922,817; 7,037,584, and 7,189,787. Water-based coating systems of thepresent invention may optionally include one or more organic solvents,which will typically be selected to be miscible in water. The liquidcarrier system of water-based coating compositions will typicallyinclude at least 50 wt-% of water, more typically at least 75 wt-% ofwater, and in some embodiments more than 90 wt-% or 95 wt-% of water.Any suitable means may be used to render the polymer of the presentinvention miscible in water. For example, the polymer may include asuitable amount of salt groups such as ionic or cationic salt groups torender the polymer miscible in water (or groups capable of forming suchsalt groups). Neutralized acid or base groups are preferred salt groups.

In some embodiments, the polymer of the present invention is covalentlyattached to one or more materials (e.g., oligomers or polymers) havingsalt or salt-forming groups to render the polymer water-dispersible. Thesalt or salt-forming group containing material may be, for example,oligomers or polymers that are (i) formed in situ prior to, during, orafter formation of the polymer of the present invention or (ii) providedas preformed materials that are reacted with a preformed, or nascent,polymer of the present invention. The covalent attachment may beachieved through any suitable means including, for example, viareactions involving carbon-carbon double bonds, hydrogen abstraction(e.g., via a reaction involving benzoyl peroxide mediated grafting viahydrogen abstraction such as, e.g., described in U.S. Pat. No.4,212,781), or the reaction of complimentary reactive functional groupssuch as occurs, e.g., in condensation reactions. In one embodiment, alinking compound is utilized to covalently attach the polyether polymerand the salt- or salt-forming-group-containing material. In certainpreferred embodiments, the one or more materials having salt orsalt-forming groups is an acrylic material, more preferably an acid- oranhydride-functional acrylic material.

In one embodiment, a water-dispersible polymer may be formed frompreformed polymers (e.g., (a) an oxirane-functional polymer, such as,e.g., a polyether polymer, preferably having at least one segment ofFormula (I) and (b) an acid-functional polymer such as, e.g., anacid-functional acrylic polymer) in the presence of an amine, morepreferably a tertiary amine. If desired, an acid-functional polymer canbe combined with an amine, more preferably a tertiary amine, to at leastpartially neutralize it prior to reaction with an oxirane-functionalpolymer preferably having at least one segment of Formula (I).

In another embodiment, a water-dispersible polymer may be formed from anoxirane-functional polymer (more preferably a polyether polymerdescribed herein) preferably having at least one segment of Formula (I)that is reacted with ethylenically unsaturated monomers to form anacid-functional polymer, which may then be neutralized, for example,with a base such as a tertiary amine. Thus, for example, in oneembodiment, a water-dispersible polymer preferably having at least onesegment of Formula (I) may be formed pursuant to the acrylicpolymerization teachings of U.S. Pat. Nos. 4,285,847 and/or 4,212,781,which describe techniques for grafting acid-functional acrylic groups(e.g., via use of benzoyl peroxide) onto epoxy-functional polymers. Inanother embodiment, acrylic polymerization may be achieved throughreaction of ethylenically unsaturated monomers with unsaturation presentin the polymer preferably containing at least one segment of Formula(I). See, for example, U.S. Pat. No. 4,517,322 and/or U.S. PublishedApplication No. 2005/0196629 for examples of such techniques.

In another embodiment, a water-dispersible polymer may be formed havingthe structure E-L-A, wherein E is an epoxy portion of the polymer formedfrom a polyether polymer described herein, A is a polymerized acrylicportion of the polymer, and L is a linking portion of the polymer whichcovalently links E to A. Such a polymer can be prepared, for example,from (a) a polyether polymer described herein preferably having abouttwo epoxy groups, (b) an unsaturated linking compound preferably having(i) a carbon-carbon double bond, a conjugated carbon-carbon double bondsor a carbon-carbon triple bond and (ii) a functional group capable ofreacting with an epoxy group (e.g., a carboxylic group, a hydroxylgroup, an amino group, an amido group, a mercapto group, etc.).Preferred linking compounds include 12 or less carbon atoms, with sorbicacid being an example of a preferred such linking compound. The acrylicportion preferably includes one or more salt groups or salt-forminggroups (e.g., acid groups such as present in α,β-ethylenically saturatedcarboxylic acid monomers). Such polymers may be formed, for example,using a BPA- and BADGE-free polyether polymer of the present inventionin combination with the materials and techniques disclosed in U.S. Pat.No. 5,830,952 or U.S. Published Application No. 2010/0068433.

In some embodiments, the coating composition of the present invention issubstantially free of acrylic components. For example, in someembodiment the coating composition includes less than about 5 wt-% orless than about 1 wt-% of polymerized acrylic monomers (e.g., a mixtureof ethylenically unsaturated monomers that include at least some monomerselected from acrylic acid, methacrylic acid, or esters thereof).

In another embodiment, a polymer preferably containing segments ofFormula (I) and including —CH₂—CH(OH)—CH₂— or —CH²—CH₂—CH(OH)— segments,which are derived from an oxirane, is reacted with an anhydride. Thisprovides acid functionality which, when combined with an amine or othersuitable base to at least partially neutralize the acid functionality,is water dispersible.

In some embodiments, the coating composition of the present invention isa low VOC coating compositions that preferably includes no greater than0.4 kilograms (“kg”) of volatile organic compounds (“VOCs”) per liter ofsolids, more preferably no greater than 0.3 kg VOC per liter of solids,even more preferably no greater than 0.2 kg VOC per liter of solids, andoptimally no greater than 0.1 kg VOC per liter of solids.

Reactive diluents may optionally be used to yield such low VOC coatingcompositions. The reactive diluent preferably functions as a solvent orotherwise lowers the viscosity of the blend of reactants. The use of oneor more reactive diluents as a “solvent” eliminates or reduces the needto incorporate a substantial amount of other cosolvents (such asbutanol) during processing.

Reactive diluents suitable for use in the present invention preferablyinclude free-radical reactive monomers and oligomers. A small amount ofreactive diluent that can undergo reaction with the polymer of thepresent invention may be used (e.g., hydroxy monomers such as 2-hydroxyethylmethacrylate, amide monomers such as acrylamide, and N-methylolmonomers such as N-methylol acrylamide). Suitable reactive diluentsinclude, for example, vinyl compounds, acrylate compounds, methacrylatecompounds, acrylamides, acrylonitriles, and the like and combinationsthereof. Suitable vinyl compounds include, for example, vinyl toluene,vinyl acetate, vinyl chloride, vinylidene chloride, styrene, substitutedstyrenes, and the like and combinations thereof. Suitable acrylatecompounds include butyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate,isobutyl acrylate, tert-butyl acrylate, methyl acrylate, 2-hydroxyethylacrylate, poly(ethylene glycol)acrylate, isobornyl acrylate, andcombinations thereof. Suitable methacrylate compounds include, forexample, butyl methacrylate, methyl methacrylate, ethyl methacrylate,isobutyl methacrylate, 2-hydroxyethyl methacrylate, poly(ethyleneglycol)methacrylate, poly(propylene glycol)methacrylate, and the likeand combinations thereof. Preferred reactive diluents include styreneand butyl acrylate. U.S. Pat. No. 7,037,584 provides additionaldiscussion of suitable materials and methods relating to the use ofreactive diluents in low-VOC packaging coating compositions.

Any suitable amount of one or more reactive diluents may optionally beemployed in coating composition of the present invention. For example,an amount of one or more reactive diluents sufficient to achieve the VOCcontent of the aforementioned low-VOC coating compositions may be used.In some embodiments, the coating composition includes at least about 1wt-%, at least about 5 wt-%, or at least 10 wt-% of polymerized reactivediluent.

In one embodiment, a polyether polymer of the present invention isblended, in any suitable order, with acrylic component (e.g., acrylicresin) and reactive diluent. The polyether polymer and the acryliccomponent are preferably reacted with one another (although they may beused as a simple blend), either before or after addition of reactivediluents, to form a polyether-acrylate copolymer. The polyether-acrylateand the reactive diluents are preferably further dispersed in water. Thereactive diluent is then preferably polymerized in the presence of thepolyether-acrylate copolymer to form a coating composition having thedesired low VOC content. In this context, the term “reactive diluent”relates to monomers and oligomers that are preferably essentiallynon-reactive with the polyether resin or any carboxylic acid moiety (orother functional group) that might be present, e.g., on the acrylicresin, under contemplated blending conditions. The reactive diluents arealso preferably capable of undergoing a reaction to form a polymer,described as an interpenetrating network with the polymer of the presentinvention, or with unsaturated moieties that may optionally be present,e.g., on an acrylic resin.

A coating composition of the present invention may also include otheroptional ingredients that do not adversely affect the coatingcomposition or a cured coating composition resulting therefrom. Suchoptional ingredients are typically included in a coating composition toenhance composition esthetics; to facilitate manufacturing, processing,handling, or application of the composition; or to further improve aparticular functional property of a coating composition or a curedcoating composition resulting therefrom. For example, the compositionthat includes a polymer of the present invention may optionally includecrosslinkers, fillers, catalysts, lubricants, pigments, surfactants,dyes, colorants, toners, coalescents, extenders, anticorrosion agents,flow control agents, thixotropic agents, dispersing agents,antioxidants, oxygen-scavenging materials, adhesion promoters, lightstabilizers, and mixtures thereof, as required to provide the desiredfilm properties. Each optional ingredient is preferably included in asufficient amount to serve its intended purpose, but not in such anamount to adversely affect a coating composition or a cured coatingcomposition resulting therefrom.

Preferred compositions are substantially free of one or both of mobileBPA or mobile BADGE, and more preferably essentially free of thesecompounds, even more preferably essentially completely free of thesecompounds, and optimally completely free of these compounds. The coatingcomposition (and preferably each ingredient included therein) is alsopreferably substantially free of one or both of bound BPA and boundBADGE, more preferably essentially free of these compounds, even morepreferably essentially completely free of these compounds, and optimallycompletely free of these compounds. In addition, preferred compositions(and preferably each ingredient included therein) are also substantiallyfree, more preferably essentially free, even more preferably essentiallycompletely free, and optimally completely free of one or more or all of:bisphenol S, bisphenol F, and the diglycidyl ether of bisphenol F orbisphenol S.

It has been discovered that coating compositions incorporating theaforementioned polymer-containing compositions may be formulated usingone or more optional curing agents (e.g., crosslinking resins, sometimesreferred to as “crosslinkers”). The choice of particular crosslinkertypically depends on the particular product being formulated. Forexample, some coating compositions are highly colored (e.g.,gold-colored coatings). These coatings may typically be formulated usingcrosslinkers that themselves tend to have a yellowish color. Incontrast, white coatings are generally formulated using non-yellowingcrosslinkers, or only a small amount of a yellowing crosslinker.

Preferred curing agents are substantially free of mobile or bound BPAand BADGE and more preferably completely free of mobile or bound BPA andBADGE. Suitable examples of such curing agents are hydroxyl-reactivecuring resins such as phenoplasts, aminoplast, blocked or unblockedisocyanates, or mixtures thereof.

Suitable phenoplast resins include the condensation products ofaldehydes with phenols. Formaldehyde and acetaldehyde are preferredaldehydes. Various phenols can be employed such as phenol, cresol,p-phenylphenol, p-tert-butylphenol, p-tert-amylphenol,cyclopentylphenol, and compounds of Formula (III) or any otherpolyhydric phenols disclosed herein.

Suitable aminoplast resins are the condensation products of aldehydessuch as formaldehyde, acetaldehyde, crotonaldehyde, and benzaldehydewith amino- or amido-group-containing substances such as urea, melamine,and benzoguanamine. Examples of suitable aminoplast crosslinking resinsinclude, without limitation, benzoguanamine-formaldehyde resins,melamine-formaldehyde resins, etherified melamine-formaldehyde, andurea-formaldehyde resins.

Examples of other generally suitable curing agents are the blocked ornon-blocked aliphatic, cycloaliphatic or aromatic di-, tri-, orpoly-valent isocyanates, such as hexamethylene diisocyanate,cyclohexyl-1,4-diisocyanate, and the like. Further non-limiting examplesof generally suitable blocked isocyanates include isomers of isophoronediisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate,diphenylmethane diisocyanate, phenylene diisocyanate, tetramethyl xylenediisocyanate, xylylene diisocyanate, and mixtures thereof. In someembodiments, blocked isocyanates are used that have an Mn of at leastabout 300, more preferably at least about 650, and even more preferablyat least about 1,000.

Polymeric blocked isocyanates are useful in certain embodiments. Someexamples of suitable polymeric blocked isocyanates include a biuret orisocyanurate of a diisocyanate, a trifunctional “trimer,” or a mixturethereof. Examples of suitable blocked polymeric isocyanates includeTRIXENE BI 7951, TRIXENE BI 7984, TRIXENE BI 7963, TRIXENE BI 7981(TRIXENE materials are available from Baxenden Chemicals, Ltd.,Accrington, Lancashire, England), DESMODUR BL 3175A, DESMODUR BL3272,DESMODUR BL3370, DESMODUR BL 3475, DESMODUR BL 4265, DESMODUR PL 340,DESMODUR VP LS 2078, DESMODUR VP LS 2117, and DESMODUR VP LS 2352(DESMODUR materials are available from Bayer Corp., Pittsburgh, Pa.,USA), or combinations thereof. Examples of suitable trimers may includea trimerization product prepared from on average three diisocyanatemolecules or a trimer prepared from on average three moles ofdiisocyanate (e.g., HMDI) reacted with one mole of another compound suchas, for example, a triol (e.g., trimethylolpropane).

The level of curing agent (e.g., crosslinker) used will typically dependon the type of curing agent, the time and temperature of the bake, themolecular weight of the binder polymer, and the desired coatingproperties. If used, the crosslinker is typically present in an amountof up to 50 wt-%, preferably up to 30 wt-%, and more preferably up to 15wt-%. If used, a crosslinker is preferably present in an amount of atleast 0.1 wt-%, more preferably at least 1 wt-%, and even morepreferably at least 1.5 wt-%. These weight percentages are based uponthe total weight of the resin solids in the coating composition.

In some embodiments, the coating composition of the present inventionare “formaldehyde-free” coatings that include, or liberate as a resultof curing, no greater than 1% by weight formaldehyde, no greater than0.5% by weight formaldehyde, no greater than 0.25% by weightformaldehyde, or no greater than 5 ppm formaldehyde. The absence ofphenolic resin and/or melamine is believed to contribute to a coatingcomposition that is appreciably free of formaldehyde.

As previously discussed, in some embodiments, the coating composition ofthe present invention includes an acrylic component which may optionallybe covalently attached to the polyether polymer described herein. Insome embodiments, the acrylic component may be present as a separatepolymer blended with the polyether polymer (in addition to any acryliccomponent that may optionally be covalently attached to the polyetherpolymer).

The coating composition of the present invention may include any amountof acrylic component suitable to produce the desired film or coatingproperties. In some acrylic-component-containing embodiments, thecoating composition includes an amount of acrylic component of at leastabout 5 wt-%, more preferably at least about 10 wt-%, and even morepreferably at least about 15 wt-%, as determined by an amount of amonomer mixture used to prepare the acrylic component and based on thetotal weight of resin solids in the coating system. In such embodiments,the coating composition preferably includes an amount of acryliccomponent of less than about 95 wt-%, more preferably less than about 75wt-%, and even more preferably less than about 30 to 40 wt-%, asdetermined by an amount of a monomer mixture used to prepare the acryliccomponent and based on the total weight of resin solids in the coatingsystem.

In certain water-based embodiments in which at least some of the acryliccomponent is covalently attached to the polyether polymer, at least aportion of the acrylic monomers used to form the acrylic component arepreferably capable of rending the polyether polymer dispersible inwater. In such embodiments, the acrylic component is preferably formedfrom an ethylenically unsaturated monomer mixture that includes one ormore α,β-unsaturated carboxylic acid. The one or more α,β-unsaturatedcarboxylic acid preferably renders the polymer water-dispersible afterneutralization with a base. Suitable α,β-unsaturated carboxylic acidmonomers include, for example, acrylic acid, methacrylic acid, crotonicacid, itaconic acid, maleic acid, mesaconic acid, citraconic acid,sorbic acid, fumaric acid, and mixtures thereof. The acrylic monomeralso can include, for example, acrylamide or methacrylamide, which canrender the polymer water dispersible. Preferred acrylic components foruse in packaging coating applications are substantially free, orcompletely free, of acrylamide- or methacrylamide-type monomers.

The acrylic monomers used to form the acrylic component can include 0%up to about 95%, by total weight of monomers, of vinyl monomers.

The acrylic component preferably includes one or more non-functionalmonomers and one or more functional monomers (more preferablyacid-functional monomers, and even more preferably acid-functionalacrylic monomers). In presently preferred embodiments, the acryliccomponent includes one or more vinyl monomers. The acrylic component ispreferably prepared through chain-growth polymerization using one ormore ethylenically unsaturated monomers.

Examples of suitable ethylenically unsaturated non-functional monomerssuch as styrene, halostyrenes, a-methylstyrene, alkyl esters of acrylicacid (e.g., methyl acrylate, ethyl acrylate, butyl acrylate, etc.),alkyl esters of methacrylic acid and/or crotonic acid (e.g., methyl,ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl, dodecyl methacrylatesand crotonates), vinyl cyclohexane, vinyl cyclooctane, vinylcyclohexene, hexanediol diacrylate, dimethyl maleate, dibutyl fumarateand similar diesters, vinyl naphthalene, vinyl toluene, vinyl acetate,vinyl propionate, vinyl cyclooctane, ally methacrylate, 2-ethylhexylacrylate, and diesters of maleic anhydride. Preferred non-functionalmonomers include styrene, ethyl acrylate, butyl methacrylate, andcombinations thereof.

Examples of functional monomers include α,β-unsaturated carboxylic acidssuch as, e.g., those previously described; amide-functional monomers;hydroxy-functional monomers (e.g., hydroxyalkyl acrylate or methacrylatemonomers such as hydroxyethyl acrylate (HEA), hydroxyethyl methacrylate(HEMA), hydroxypropyl acrylate (HPA), hydroxypropyl methacrylate (HPMA),etc.); oxirane-functional monomers (e.g., glycidyl acrylate and glycidylmethacrylate) and variations and combinations thereof. Preferrednon-functional monomers include styrene, ethyl acrylate, butylmethacrylate, and combinations thereof. Preferred functional monomersinclude acrylic acid, methacrylic acid, and combinations thereof.

The combination and/or ratio(s) of the above monomers of the acryliccomponent may be adjusted to provide a desired coating or film property.Preferably, at least a portion of the above monomers of the acryliccomponent are capable of rendering the resin system dispersible in anaqueous carrier. Examples of monomers capable of rendering the resinsystem dispersible in an aqueous carrier include acid-functionalmonomers that form salt groups upon neutralization with a base.

While not intending to be bound by theory, it is believed that, forcertain embodiments of the present invention, the Tg of the acryliccomponent is a factor that can contribute to coating compositionsexhibiting suitable resistance to retort processes associated withcertain food and beverage products. In general, the Fox equation may beemployed to calculate the theoretical Tg of the acrylic component. Insome embodiments, the acrylic component has a Tg of at least about 40°C., preferably at least about 60° C., more preferably at least about 80°C., and even more preferably at least about 90° C. By way of example, awater-dispersible polymer having an E-L-A described previously hereincan include an acrylic component having such a Tg. The acrylic componentpreferably has a Tg of less than about 280° C., more preferably lessthan about 220° C., even more preferably less than about 180° C., evenmore preferably less than about 160° C., and optimally less than about150° C. In some embodiments, the acrylic component has a Tg of less thanabout 130° C., or less than about 120° C. In some embodiments, theacrylic component has a Tg greater than about 100° C., more preferablyfrom about 100° C. to about 120° C.

In other embodiments, it may be beneficial to use an acrylic componenthaving a Tg of less than 50° C., 40° C., or even less than 30° C. Forexample, in certain embodiments in which high resistance to retortprocessing conditions is not a requirement, such an acrylic componentmay be used to confer one or more other desired properties.

A coating composition of the present invention may also include otheroptional polymers that do not adversely affect the coating compositionor a cured coating composition resulting therefrom. Such optionalpolymers are typically included in a coating composition as a fillermaterial, although they can also be included, for example, as a binderpolymer, a crosslinking material, or to provide desirable properties.One or more optional polymers (e.g., filler polymers) can be included ina sufficient amount to serve an intended purpose, but not in such anamount to adversely affect a coating composition or a cured coatingcomposition resulting therefrom.

Such additional polymeric materials can be nonreactive, and hence,simply functionas fillers. Such optional nonreactive filler polymersinclude, for example, polyesters, acrylics, polyamides, polyethers, andnovalacs. Alternatively, such additional polymeric materials or monomerscan be reactive with other components of the composition (e.g. anacid-functional or unsaturated polymer). If desired, reactive polymerscan be incorporated into the compositions of the present invention, toprovide additional functionality for various purposes, includingcrosslinking or dispersing the polymer of the present invention intowater. Examples of such reactive polymers include, for example,functionalized polyesters, acrylics, polyamides, and polyethers.Preferred optional polymers are substantially free or essentially freeof bound BPA and BADGE, and more preferably essentially completely freeor completely free of bound such compounds.

One preferred optional ingredient is a catalyst to increase the rate ofcure. Examples of catalysts, include, but are not limited to, strongacids (e.g., phosphoric acid, dodecylbenzene sulphonic acid (DDBSA),available as CYCAT 600 from Cytec, methane sulfonic acid (MSA),p-toluene sulfonic acid (pTSA), dinonylnaphthalene disulfonic acid(DNNDSA), and triflic acid); quaternary ammonium compounds; phosphorouscompounds; and tin, titanium, and zinc compounds. Specific examplesinclude, but are not limited to, a tetraalkyl ammonium halide, atetraalkyl or tetraaryl phosphonium iodide or acetate, tin octoate, zincoctoate, triphenylphosphine, and similar catalysts known to personsskilled in the art. If used, a catalyst is preferably present in anamount of at least 0.01 wt-%, and more preferably at least 0.1 wt-%,based on the weight of nonvolatile material in the coating composition.If used, a catalyst is preferably present in an amount of no greaterthan 3 wt-%, and more preferably no greater than 1 wt-%, based on theweight of nonvolatile material in the coating composition.

Another useful optional ingredient is a lubricant (e.g., a wax), whichfacilitates manufacture of fabricated metal articles (e.g., closures andfood or beverage can ends) by imparting lubricity to sheets of coatedmetal substrate. Non-limiting examples of suitable lubricants include,for example, natural waxes such as Carnauba wax or lanolin wax,polytetrafluoroethane (PTFE) and polyethylene-type lubricants. If used,a lubricant is preferably present in the coating composition in anamount of at least 0.1 wt-%, and preferably no greater than 2 wt-%, andmore preferably no greater than 1 wt-%, based on the total weight ofnonvolatile material in the coating composition.

Another useful optional ingredient is a pigment, such as titaniumdioxide. If used, a pigment is present in the coating composition in anamount of no greater than 70 wt-%, more preferably no greater than 50wt-%, and even more preferably no greater than 40 wt-%, based on thetotal weight of solids in the coating composition.

Surfactants can be optionally added to the coating composition, e.g., toaid in flow and wetting of the substrate. Examples of surfactants,include, but are not limited to, nonylphenol polyethers and salts andsimilar surfactants known to persons skilled in the art. If used, asurfactant is preferably present in an amount of at least 0.01 wt-%, andmore preferably at least 0.1 wt-%, based on the weight of resin solids.If used, a surfactant is preferably present in an amount no greater than10 wt-1%, and more preferably no greater than 5 wt-%, based on theweight of resin solids.

In some embodiments, the polyether polymer of the invention is includedin a layer of a monolayer or multilayer coating system including a layerincorporating a thermoplastic dispersion (e.g., a halogenated polyolefindispersion such as, e.g., a polyvinylchloride (“PVC”) organosol). In oneembodiment, the polyether polymer is included a primer layer of such amultilayer coating system including another layer (e.g., a top layer)incorporating a thermoplastic dispersion. Such multilayer coatingsystems are described in the application entitled “Container CoatingSystem” ( U.S. Provisional Application No. 61/681,590) filed on Aug. 9,2012. In another embodiment, the polyether polymer is included in thelayer incorporating the thermoplastic dispersion, e.g., as a stabilizerfor PVC and/or as a co-resin, which is described in the applicationentitled “Stabilizer and Coating Compositions Thereof” (U.S. ProvisionalApplication No. 61/681,602) filed on Aug. 9, 2012.

In some embodiments, the coating composition is “PVC-free.” That is, insome embodiments, the coating composition preferably contains less than2 wt-% of vinyl chloride materials, more preferably less than 0.5 wt-%of vinyl chloride materials, and even more preferably less than 1 ppm ofvinyl chloride materials.

The coating composition of the present invention can be present as alayer of a mono-layer coating system or one or more layers of amulti-layer coating system. The coating composition can be used as aprimer coat, an intermediate coat, a top coat, or a combination thereof.The coating thickness of a particular layer and the overall coatingsystem will vary depending upon the coating material used, thesubstrate, the coating application method, and the end use for thecoated article. Mono-layer or multi-layer coating systems including oneor more layers formed from a coating composition of the presentinvention may have any suitable overall coating thickness, but willtypically have an overall average dry coating thickness of from about 1to about 60 microns and more typically from about 2 to about 15 microns.Typically, the average total coating thickness for rigid metal food orbeverage can applications will be about 3 to about 10 microns. Coatingsystems for closure applications may have an average total coatingthickness up to about 15 microns. In certain embodiments in which thecoating composition is used as an interior coating on a drum (e.g., adrum for use with food or beverage products), the total coatingthickness may be approximately 25 microns.

The coating composition of the present invention may be applied to asubstrate either prior to, or after, the substrate is formed into anarticle (such as, for example, a food or beverage container or a portionthereof). In one embodiment, a method is provided that includes:applying a coating composition described herein to a metal substrate(e.g., applying the composition to the metal substrate in the form of aplanar coil or sheet), hardening the composition, and forming (e.g., viastamping) the substrate into a packaging container or a portion thereof(e.g., a food or beverage can or a portion thereof). For example,riveted beverage can ends having a cured coating of the presentinvention on a surface thereof can be formed in such a process. Inanother embodiment, the coating composition is applied to a preformedmetal food or beverage can, or a portion thereof. For example, in someembodiments, the coating composition is spray applied to an interiorsurface of a preformed food or beverage can (e.g., as typically occurswith “two-piece” food or beverage cans). After applying the coatingcomposition onto a substrate, the composition can be cured using avariety of processes, including, for example, oven baking by eitherconventional or conventional methods, or any other method that providesan elevated temperature suitable for curing the coating. The curingprocess may be performed in either discrete or combined steps. Forexample, substrates can be dried at ambient temperature to leave thecoating compositions in a largely un-crosslinked state. The coatedsubstrates can then be heated to fully cure the compositions. In certaininstances, coating compositions of the present invention can be driedand cured in one step.

The cure conditions will vary depending upon the method of applicationand the intended end use. The curing process may be performed at anysuitable temperature, including, for example, oven temperatures in therange of from about 100° C. to about 300° C., and more typically fromabout 177° C. to about 250° C. If metal coil is the substrate to becoated, curing of the applied coating composition may be conducted, forexample, by heating the coated metal substrate over a suitable timeperiod to a peak metal temperature (“PMT”) of preferably greater thanabout 350° F. (177° C.). More preferably, the coated metal coil isheated for a suitable time period (e.g., about 5 to 900 seconds, moretypically about 5 to 30 seconds) to a PMT of at least about 425° F.(218° C.).

The coating compositions of the present invention are particularlyuseful for coating metal substrates. The coating compositions may beused to coat packaging articles such as a food or beverage container, ora portion thereof. In preferred embodiments, the container is a food orbeverage can and the surface of the container is the surface of a metalsubstrate. The polymer can be applied to a metal substrate either beforeor after the substrate is formed into a can (e.g., two-piece cans,three-piece cans) or portions thereof, whether it be a can end or canbody. Preferred polymers of the present invention are suitable for usein food-contact situations and may be used on the inside of such cans.They are particularly useful on the interior of two-piece or three-piececan ends or bodies.

The metal substrate used in forming rigid food or beverage cans, orportions thereof, typically has a thickness in the range of about 0.005inches to about 0.025 inches. Electro tinplated steel, cold-rolledsteel, and aluminum are commonly used as metal substrates for food orbeverage cans, or portions thereof. In embodiments in which a metal foilsubstrate is employed in forming, e.g., a packaging article, thethickness of the metal foil substrate may be even thinner that thatdescribed above.

The coating compositions of the present invention may be suitable, forexample, for spray coating, coil coating, wash coating, sheet coating,and side seam coating (e.g., food can side seam coating). A furtherdiscussion of such application methods is provided below. It iscontemplated that coating compositions of the present invention may besuitably used in each of these application methods discussed furtherbelow, including the end uses associated therewith.

Spray coating includes the introduction of the coated composition intothe inside of a preformed packaging container. Typical preformedpackaging containers suitable for spray coating include food cans, beerand beverage containers, and the like. The spray process preferablyutilizes a spray nozzle capable of uniformly coating the inside of thepreformed packaging container. The sprayed preformed container is thensubjected to heat to remove any residual carriers (e.g., water orsolvents) and harden the coating.

In one embodiment, the coating composition of the present invention is awater-based “inside spray” coating suitable for spray application to theinterior surfaces of a two-piece food or beverage can, which preferablyincludes from about 15 to about 40 wt-% of nonvolatile materials, morepreferably 15 to 25 wt-% nonvolatile materials for inside spray fortwo-piece beer and beverage cans. Preferred inside spray coatings of thepresent invention are capable of passing both the Initial Metal Exposureand Metal Exposure After Drop Can Damage tests described in the belowTest Methods section.

A coil coating is described as the coating of a continuous coil composedof a metal (e.g., steel or aluminum). Once coated, the coating coil issubjected to a short thermal, ultraviolet, and/or electromagnetic curingcycle, for hardening (e.g., drying and curing) of the coating. Coilcoatings provide coated metal (e.g., steel and/or aluminum) substratesthat can be fabricated into formed articles, such as two-piece drawnfood cans, three-piece food cans, food can ends, drawn and ironed cans,beverage can ends, and the like. In one embodiment, the coatingcomposition of the present invention is a water-based coatingcomposition that is applied to aluminum or steel coating from whichriveted beverage can ends are subsequently fabricated. Accordingly, incertain preferred embodiments, the coating composition is capable ofpassing the Metal Exposure test described in the below Test Methods.

A wash coating is commercially described as the coating of the exteriorof two-piece drawn and ironed (“D&I”) cans with a thin layer ofprotectant coating. The exterior of these D&I cans are “wash-coated” bypassing pre-formed two-piece D&I cans under a curtain of a coatingcomposition. The cans are inverted, that is, the open end of the can isin the “down” position when passing through the curtain. This curtain ofcoating composition takes on a “waterfall-like” appearance. Once thesecans pass under this curtain of coating composition, the liquid coatingmaterial effectively coats the exterior of each can. Excess coating isremoved through the use of an “air knife.” Once the desired amount ofcoating is applied to the exterior of each can, each can is passedthrough a thermal, ultraviolet, and/or electromagnetic curing oven toharden (e.g., dry and cure) the coating. The residence time of thecoated can within the confines of the curing oven is typically from 1minute to 5 minutes. The curing temperature within this oven willtypically range from 150° C. to 220° C.

A sheet coating is described as the coating of separate pieces of avariety of materials (e.g., steel or aluminum) that have been pre-cutinto square or rectangular “sheets.” Typical dimensions of these sheetsare approximately one square meter. Once coated, the coating is hardened(e.g., dried and cured) and the coated sheets are collected and preparedfor subsequent fabrication. Sheet coatings provide coated metal (e.g.,steel or aluminum) substrate that can be successfully fabricated intoformed articles, such as two-piece drawn food cans, three-piece foodcans, food can ends, drawn and ironed cans, beverage can ends(including, e.g., riveted beverage can ends having a rivet for attachinga pull tab thereto), and the like. In one embodiment, the coatingcomposition of the present invention is a solvent-based coatingcomposition that is applied to steel or aluminum sheets that aresubsequently fabricated into the above described packaging articles.

A side seam coating is described as the application of a powder coatingor the spray application of a liquid coating over the welded area offormed three-piece food cans. When three-piece food cans are beingprepared, a rectangular piece of coated substrate is formed into acylinder. The formation of the cylinder is rendered permanent due to thewelding of each side of the rectangle via thermal welding. Once welded,each can typically requires a layer of coating, which protects theexposed “weld” from subsequent corrosion or other effects to thecontained foodstuff. The coatings that function in this role are termed“side seam stripes.” Typical side seam stripes are spray applied andcured quickly via residual heat from the welding operation in additionto a small thermal, ultraviolet, and/or electromagnetic oven.

Other commercial coating application and curing methods are alsoenvisioned, for example, electrocoating, extrusion coating, laminating,powder coating, and the like.

In certain preferred embodiments, the coating composition of the presentinvention is capable of exhibiting one or more (and in some embodimentsall) of the following coating properties: good blush resistance, goodcorrosion resistance, good stain resistance, good flexibility (e.g.,good resistance to drop can damage, suitability for use as a beveragecan end coating, etc), and good adhesion to metal substrate), whensubjected to the testing described below in Examples.

In embodiments in which the coating composition is intended for use asan internal packaging coating, the coating composition, when suitablycured, preferably has suitable corrosion resistance to withstandprolonged contact with the packaged product, as well as any processingconditions, without unsuitably degrading. Preferred interior packagingcoating compositions, when applied on suitable metal substrate (e.g., ametal substrate used in the below Examples section) at a coatingthickness consistent with that typically used in the particularpackaging end use and suitably cured, are capable of withstanding beingimmersed in a 2% aqueous NaCl solution for 90 minutes at a temperatureof 121° C. and a pressure of 1.05 kilograms per square centimeterwithout exhibiting any unsuitable film integrity reduction such asblistering or loss of adhesion (e.g., using the methods of the TestMethods section). Preferred interior beverage can end coatings arepreferably capable of passing the above test using an aqueous 1% citricacid solution in place of the 2% NaCl solution.

The polymer of the present invention can be used in powder coatingapplications, e.g., for use in forming an adherent polymeric coating.Thus, in some embodiments, the coating composition of the presentinvention is a powder coating composition that preferably does notinclude a liquid carrier (although it may include trace amounts ofresidual water or organic solvent). The powder coating composition ispreferably in the form of a finely divided, free flowing powder. Inpreferred embodiments, the powder composition is a thermosettable powdercomposition that forms a thermoset coating when suitably cured. Thediscussion that follows relates to powder coating embodiments of thepresent invention.

The powder coating composition of the present invention may beparticularly useful in end uses in which a coated substrate is intendedto contact substances for consumption by humans or intimate contact withhumans. For example, the powder coating compositions may be used tocoat: surfaces of food or beverage containers, cosmetic containers, ormedicinal containers, surfaces of valves and fittings, includingsurfaces intended for contact with potable water or other consumableliquids; surfaces of pipes, including internal surfaces of water pipesor other liquid conveying pipes; and surfaces of tanks, includinginternal surfaces of water tanks such as bolted steel tanks. For powdercoatings that will contact potable water, the cured powder coatingcomposition should preferably comply with ANSI/NSF standard 61. Someexamples of fittings include articles for use in liquid conveyingsystems (e.g., for use in conveying potable water) such as connectors(e.g., threaded or flanged connectors), elbows, flow splitters (e.g.,T-fittings, etc.), backflow preventers, pipe end caps, and the like.

The powder coating composition preferably includes at least afilm-forming amount of the polymer of the present invention, which inpreferred embodiments is a polyether polymer having segments of Formula(I). In order to facilitate stability of the powder coating compositionduring storage prior to use, a polymer of the present invention ispreferably selected that has a Tg of at least about 40° C., morepreferably at least about 50° C., and even more preferably at leastabout 60° C. The powder coating composition preferably includes at leastabout 50 wt-%, more preferably at least 70 wt-%, and even morepreferably at least 90 wt-% of the polymer of the present invention,based on total resin solids.

Powder coating compositions typically utilize binder polymers having adifferent molecular weight (typically a lower molecular weight) thanthose of liquid packaging coating compositions for use on metal food orbeverage cans. When used in powder coating compositions, the polymer ofthe present invention preferably has a number average molecular weight(Mn) of at least about 1,000, more preferably at least about 1,200, andeven more preferably at least about 1,500. In such applications, thepolymer of the present invention preferably has an Mn of less than about6,000, more preferably less than about 5,000, and even more preferablyless than about 4,000.

The powder coating composition preferably includes at least one basepowder that includes the polymer of the present invention. The basepowder may further include one or more optional ingredients, which mayinclude any suitable ingredients disclosed herein. The base powderpreferably includes the polymer of the present invention as a majorcomponent on a weight basis, and more preferably includes at least 50wt-% of the polymer. In some embodiments, the polymer of the presentinvention comprises all or substantially all of the base powder.

The particles of the base powder may be of any suitable size.Preferably, the particles of the base powder exhibit a particle sizediameter of from about 1 micron to about 200 microns, more preferablyfrom about 10 to about 150 microns.

The base powder may exhibit any suitable distribution of particle sizes.In some embodiments, the median particle size of the base powder ispreferably at least about 20 microns, more preferably at least about 30microns, and even more preferably at least about 40 microns. In someembodiments, the median particle size is preferably less than about 150microns, more preferably less than about 100 microns, and even morepreferably less than about 60 microns. The median particle sizesreferenced in this paragraph are median diameter particle sizesexpressed on a volume basis, which may be determined, for example, vialaser diffraction.

Powder compositions of the present invention may also contain one ormore other optional ingredients. The optional ingredients preferably donot adversely affect the powder compositions or articles formedtherefrom. Such optional ingredients may be included, for example, toenhance aesthetics; to facilitate manufacturing, processing, and/orhandling of powder compositions or articles formed therefrom; and/or tofurther improve a particular property of powder compositions or articlesformed therefrom. Each optional ingredient is preferably included in asufficient amount to serve its intended purpose, but not in such anamount to adversely affect a powder composition or a cured coatingresulting therefrom. The one or more optional ingredients may be presentin a same or different particle than the polymer of the presentinvention, or a combination thereof. In preferred embodiments, one ormore optional ingredients are present in the particles of the basepowder along with the polymer of the present invention. If present inparticles other than those of the base powder, the particles of theoptional ingredient(s) preferably have a particle size in the generalrange of the particles sizes of the base powder.

The powder composition preferably includes one or more optional curingagents (e.g., crosslinkers). Suitable curing agents may include phenoliccrosslinkers, preferably BPA-free phenolic crosslinkers; dicyandiamide,which may be optionally substituted; carboxyl-functional compounds suchas, e.g., carboxyl-functional polyester resins or carboxyl-functionalacrylic resins; and combinations thereof. The powder composition mayinclude any suitable amount of the one or more crosslinkers. In someembodiments, crosslinker is present in the powder composition in anamount of up to about 15 wt-%, preferably up to about 10 wt-%, and morepreferably up to about 5 wt-%, based on the total weight of the powdercoating composition. If used, crosslinker is preferably present in anamount of at least about 0.1 wt-%, more preferably at least about 0.5wt-%, and even more preferably at least about 1 wt %, based on the totalweight of the powder coating composition.

An optional cure accelerator may be present in the powder coatingcomposition to facilitate cure. When used, the powder coatingcomposition typically includes from about 0.1 wt-% to about 3 wt-% ofone or more cure accelerators. 2-methylimidazole is an example of apreferred cure accelerator. Other suitable cure accelerators may includeimidazoles, phosphonium salts, tertiary amines, quaternary ammoniumsalts, anhydrides, polyamides, aliphatic amines, epoxy resin-amineadducts, and combinations thereof.

The powder coating composition may optionally include one or more flowcontrol agents to improve the flow, wetting, and/or leveling propertiesof the cured film. If used, flow control agents are typically present inan amount of about 0.01 wt-% to about 5 wt-%, more typically from about0.2 wt-% to about 2 wt-%, based on the total weight of the powdercoating composition. Examples of suitable flow control agents includepolyacrylates such as poly(2-ethylhexyl acrylate) and variousco-polymers of 2-ethylhexyl acrylate.

The powder coating composition may optionally include one or morefluidizing agents to facilitate the preparation of a free-flowing powdercomposition. If used, fluidizing agent is typically present in an amountof about 0.01 wt-% to about 5 wt-%, more typically from about 0.05 wt-%to about 0.5 wt-%, based on the total weight of the powder coatingcomposition. Suitable fluidizing agents include, for example, fumedsilicas of a suitable particle size. Such fluidizing agents maypreferably be added after the melt blending process, such as to theextruded flake before or after grinding.

Inorganic filler and/or colored pigment may optionally be included inthe powder coating compositions. Examples of suitable such materials mayinclude calcium silicates such as, e.g., wollastonite; barium sulfate;calcium carbonate; mica; talc; silica; iron oxide; titanium dioxide;carbon black; phthalocyanines; chromium oxide; and combinations thereof.

The powder coating compositions can be prepared via any suitablemethods. In one embodiment, some or all of the ingredients aremelt-blended together, which may be accomplished, for example, usingconventional single-screw or twin-screw extruders. The temperature ofthe melt-blending step is preferably controlled to avoid any appreciablecross-linking. Typically, a melt-blending temperature is selected suchthat the temperature of the molten blend does not exceed about 100° C.to about 150° C. The ingredients may optionally be pre-mixed prior tomelt blending. After melt blending and cooling, the resulting blend,which is typically an extrudate, can be processed into powder usingconventional milling techniques. The resulting milled powder canoptionally be sieved to remove particles falling outside the desiredparticle size range. The powder can optionally be mixed with one or moreadditional powders to form the finished powder coating composition. Forexample, in some embodiments, the milled powder is combined withfluidizing agent powder either before or after optional sieving.

The powder coatings compositions can be applied to substrate using anysuitable method. Typically, the substrate is a metal substrate (e.g.,cast iron, steel, etc.), which may be bare metal or may be optionallypretreated and/or primed. One suitable such method is the electrostaticspray application of charged powder to substrate. Alternatively, thesubstrate may be applied, for example, by dipping the substrate in afluidized powder bed. In a preferred embodiment, the powder is appliedto heated substrate that has been heated to between 190° C. and 240° C.Upon contacting the heated metal substrate, the powder melts, reacts,and forms a continuous coating that is preferably smooth and uniform. Inanother embodiment, the powder is applied to a near ambient temperaturesubstrate and the powder coated substrate is then heated to atemperature sufficient to cause the powder to melt, react, and form acontinuous coating that is preferably smooth and uniform.

The melting and curing (e.g., crosslinking) of the powder compositionmay be performed in combined or discrete heating steps. In presentlypreferred embodiments, a combined heating step is used in which thepowder coating composition is heated to a temperature sufficient to bothmelt the powder and cure the resulting continuous coating. The baketemperature and the duration of the bake will vary depending upon avariety of factors, including, for example, the end use. For purposes ofcuring the coating, the bake temperature is typically at least about150° C., and more typically at least about 200° C. In general, a lowercure temperature may be used if a longer cure time is employed. The curetemperature typically will not exceed about 240° C. The cure time mayrange, for example, from about 30 seconds to about 30 minutes, dependingupon the cure temperature and the end use.

The thickness of the cured powder coating will vary depending upon theparticular end use. However, typically the cured powder coating willhave an average coating thickness in the range of about 25 to about1,500 microns, and more typically about 50 to about 500 microns. In someembodiments, an average coating thickness in the range of about 125 toabout 300 microns is used.

EMBODIMENTS

Some additional non-limiting embodiments are provided below to furtherexemplify the present invention.

Embodiment 1

A polymer, more preferably a polyether polymer, having one or moresegments of the below Formula (I):

wherein:

-   -   each of the pair of oxygen atoms depicted in Formula (I) is        preferably present in an ether or ester linkage, more preferably        an ether linkage;    -   H denotes a hydrogen atom, if present;    -   each R¹ is independently an atom or group preferably having an        atomic weight of at least 15 Daltons, wherein each of the        phenylene groups depicted in Formula (I) preferably includes at        least one R¹ attached to the ring at an ortho or meta position        relative to the oxygen atom;    -   v is independently 0 to 4, preferably 1 to 4, more preferably 2        to 4;    -   w is 4;    -   R² if present, is preferably a divalent group;    -   n is 0 or 1, with the proviso that if n is 0, the phenylene        groups depicted in Formula (I) can optionally join to form a        fused ring system with each other (e.g., a substituted        naphthalene group), in which case w is 3 and v is 0 to 4;    -   t is 0 or 1;    -   wherein two or more R¹ and/or R² groups can join to form one or        more cyclic groups; and    -   the polymer is preferably free of bound BPA or BADGE.

Embodiment 2

A polymer, more preferably a polyether polymer, that is the reactionproduct of ingredients including:

wherein:

-   -   R¹, R², n, t, v, and w are as described above for Formula (I);    -   each of the phenylene groups depicted in Formula (I) includes at        least one R¹ that is preferably attached to the ring at an ortho        or meta position relative to the depicted oxygen atom, more        preferably an ortho position;    -   s is 0 to 1;    -   R³, if present, is a divalent group, more preferably a divalent        organic group; and    -   preferably each R⁴ is independently a hydrogen atom, a halogen        atom, or a hydrocarbon group that may include one or more        heteroatoms.

Embodiment 3

A coating composition comprising the polymer of Embodiments 1 or 2(preferably in at least a film-forming amount) and one or more optionalingredients selected from a crosslinker and a liquid carrier.

Embodiment 4

An article (preferably a packaging article, more preferably a food orbeverage container or a portion thereof) having a substrate (preferablya metal substrate), wherein the coating composition of Embodiment 3 isapplied on at least a portion of the substrate.

Embodiment 5

A method comprising: providing a substrate (preferably a metalsubstrate) and applying the coating composition of Embodiment 3 on atleast a portion of the substrate.

Embodiment 6

A polymer, coating composition, article, or method of any precedingembodiment, wherein the polymer and/or coating composition is at leastsubstantially free of BPA or BADGE.

Embodiment 7

A polymer, coating composition, article, or method of any precedingembodiment, wherein each of the depicted phenylene groups in Formula (I)or Formula (II) has at least one ortho or meta R¹ (relative to thedepicted oxygen) that is an organic group, more preferably an organicgroup that includes from 1 to 4 carbon atoms, even more preferably 1 to2 carbon atoms.

Embodiment 8

A polymer, coating composition, article, or method of any precedingembodiment, wherein each of the depicted phenylene groups in Formula (I)or Formula (II) has at least one ortho or meta R¹ (relative to thedepicted oxygen) that is independently a group selected from substitutedor unsubstituted methyl groups, ethyl groups, propyl groups, butylgroups, or an isomer thereof.

Embodiment 9

A polymer, coating composition, article, or method of any precedingembodiment, wherein each phenylene group depicted in Formula (I) orFormula (II) includes R's attached to the ring at both ortho positionsrelative to the depicted oxygen atom.

Embodiment 10

A polymer, coating composition, article, or method of any precedingembodiment, wherein the segment of Formula (I) is derived from4,4′-methylenebis(2,6-di-t-butylphenol);2,2′-methylenebis(4-methyl-6-t-butylphenol);4,4′-methylenebis(2,6-dimethylphenol);4,4′butylidenebis(2-t-butyl-5-methylphenol), 2,5-di-t-butylhydroquinone,a derivative thereof, or a diepoxide thereof (more preferably adiglycidyl ether thereof).

Embodiment 11

A polymer, coating composition, article, or method of any precedingembodiment, wherein each phenylene group depicted in Formula (I) orFormula (II) includes at least one R¹ attached to the ring at an orthoposition relative to the depicted oxygen atom.

Embodiment 12

A polymer, coating composition, article, or method of any precedingembodiment, wherein both t and n are 1.

Embodiment 13

A polymer, coating composition, article, or method of any precedingembodiment, wherein both t and n are 1 and R^(z) has an atomic mass ofless than 500, more less than 200, or less than 100.

Embodiment 4

A polymer, coating composition, article, or method of any precedingembodiment, wherein R² is an organic group containing either (i) 1 or 2carbon atoms or (ii) at least: 8, 9, 10, 11, 12, 13 or 14 carbon atoms.

Embodiment 14.5

A polymer, coating composition, article, or method of any precedingembodiment, wherein both t and n are 1 and R² is an organic group of theformula —C(R⁷)(R⁸)—, wherein R⁷ and R are each independently a hydrogenatom, a halogen atom, an organic group, a sulfur-containing group, anitrogen-containing group, or any other suitable group that ispreferably substantially non-reactive with an epoxy group, and whereinR⁷ and R¹ can optionally join to form a cyclic group.

Embodiment 15

A polymer, coating composition, article, or method of any precedingembodiment, wherein the polymer (preferably a polyether polymer)includes one or more pendant hydroxyl groups attached to backbone carbonatoms.

Embodiment 16

A polymer, coating composition, article, or method of any precedingembodiment, wherein a backbone of the polymer includes one or both of—CH₂—CH(OH)—CH₂— or —CH²—CH₂—CH(OH)— segments.

Embodiment 17

A polymer, coating composition, article, or method of any precedingembodiment, wherein the —CH₂—CH(OH)—CH₂— or —CH²—CH₂—CH(OH)— segmentsare attached to each of the ether oxygen atoms depicted in Formula (I).

Embodiment 18

A polymer, coating composition, article, or method of any precedingembodiment, wherein the polymer (preferably a polyether polymer) has aTg of at least 60° C., more preferably at least 70° C., even morepreferably at least 80° C.

Embodiment 19

A polymer, coating composition, article, or method of any precedingembodiment, wherein aryl or heteroaryl groups (more typically phenylenegroups) constitute at least 20 wt-% of the polyether polymer, based onthe total weight of aryl and heteroaryl groups present in the polymerrelative to the weight of the polymer.

Embodiment 20

A polymer, coating composition, article, or method of any precedingembodiment, wherein the polymer includes a plurality of segments ofFormula (I) and, in some embodiments, includes at least: 1 wt-%, 5 wt-%,10 wt-%, 20 wt-%, 30 wt-%, or 50 wt-% of the segments of Formula (I).

Embodiment 21

A polymer, coating composition, article, or method of any precedingembodiment, wherein the polymer is a polyether polymer and the polyetherpolymer (or polyether polymer fraction of a copolymer such as apolyether-acrylic copolymer) includes at least 20 wt-%, at least 30wt-%, or at least 50 wt-% of segments of Formula (I).

Embodiment 22

A polymer, coating composition, article, or method of any precedingembodiment, wherein the polymer and/or coating composition is at leastsubstantially free of acrylic (e.g., includes less than 1 wt-% ofpolymerized acrylic monomers, if any).

Embodiment 23

A polymer, coating composition, article, or method of any precedingembodiment, wherein the polymer includes a plurality of segments ofFormula (I), wherein t is 1 and R² includes one or more ester backboneester linkages.

Embodiment 24

A polymer, coating composition, article, or method of Embodiment 23,wherein R² includes one or more monocyclic or polycyclic groups.

Embodiment 25

A polymer, coating composition, article, or method of any precedingembodiment, wherein the polymer comprises a polyether polymer that is areaction product of ingredients including (i) a diepoxide having asegment of Formula (I) or a diepoxide compound of Formula (II) and (ii)a dihydric phenol.

Embodiment 26

A polymer, coating composition, article, or method of Embodiment 25,wherein one or more (and more preferably all) of the following are true:

-   -   (a) the diepoxide of (i) is formed from a dihydric phenol that        does not exhibit appreciable estrogenic activity);    -   (b) the diepoxide of (i) does not exhibit mutagenicity or any        other unsuitable genotoxicity (e.g., the diepoxide is        non-genotoxic in the comet assay); and    -   (c) the dihydric phenol of (ii) does not exhibit appreciable        estrogenic activity.

Embodiment 27

A polymer, coating composition, article, or method of Embodiment 25,wherein the dihydric phenol is of the formula:HO—Ar—(R⁵)_(w)—Z—R⁶—Z—(R⁵)_(w)—Ar—OHwherein:

-   -   each Ar is independently a divalent aryl group or heteroaryl        group (more typically a substituted or unsubstituted phenylene        group);    -   each R⁵, if present, is independently a divalent organic group;    -   R⁶ is a divalent organic group;    -   each Z is independently an ester linkage of either        directionality (e.g., —C(O)—O— or —O—C(O)—); and    -   each w is 0 or 1.

Embodiment 28

A polymer, coating composition, article, or method of any precedingembodiment, wherein the polymer has an Mn of from 2,000 to 20,000.

Embodiment 29

A coating composition, article, or method of any preceding embodiment,wherein the coating composition, by weight total resin solids, includesat least 5 wt-% or 10 wt-% of the polyether polymer.

Embodiment 30

A coating composition, article, or method of any preceding embodiment,wherein the coating composition is a food-contact coating.

Embodiment 31

A coating composition, article, or method of any preceding embodiment,wherein the coating composition is one of: a solvent-based coatingcomposition or a water-based coating composition.

Embodiment 32

A coating composition, article, or method of any preceding embodiment,wherein the coating composition is a water-based coating compositionthat is at least substantially free of acrylic.

Embodiment 33

A method of any preceding embodiment, wherein the substrate is formedinto a packaging container or a portion thereof (e.g., a food orbeverage container or a portion thereof) after application of thecoating composition.

Embodiment 34

A method or article of any preceding embodiment, wherein the coatedarticle comprises a metal food or beverage container, a cosmeticcontainer, a pharmaceutical container, or a portion thereof (e.g., a canend) having the coating composition applied to one or more of: anexterior surface or an interior (i.e., product-contact) surface.

Embodiment 35

A coating composition, article, or method of any of Embodiments 1-30,33, and 34, wherein the coating composition comprises a powder coatingcomposition.

Embodiment 36

The article or Embodiment 35, wherein the article is an article forconveying or storing potable water (e.g., a water valve, water fitting,water pipe, a bolted steel water tank or a panel for use therein, etc.).

Embodiment 37

The polymer, coating composition, article, or method of any precedingembodiment wherein one or both of the polymer or the coating compositionare at least substantially free, more preferably essentially free, evenmore preferably essentially completely free, and optimally completelyfree of bound polyhydric phenol compounds, or epoxides thereof, thatexhibit a degree of estrogen agonist activity, in a competent in vitrohuman estrogen receptor assay (e.g., the MCF-7 assay) greater than thatexhibited by 4,4′-(propane-2,2-diyl)diphenol in the assay.

Embodiment 38

The polymer, coating composition, article, or method of any precedingembodiment wherein one or both of the polymer or the coating compositionare at least substantially free, more preferably essentially free, evenmore preferably essentially completely free, and optimally completelyfree of bound polyhydric phenol compounds, or epoxides thereof, thatexhibit a degree of estrogen agonist activity, in a competent in vitrohuman estrogen receptor assay (e.g., the MCF-7 assay) greater than thatexhibited by bisphenol S in the assay.

Embodiment 39

The polymer, coating composition, article, or method of any precedingembodiment wherein one or both of the polymer or the coating compositionare at least substantially free, more preferably essentially free, evenmore preferably essentially completely free, and optimally completelyfree of bound polyhydric phenol compounds, or epoxides thereof, thatexhibit a degree of estrogen agonist activity, in a competent in vitrohuman estrogen receptor assay (e.g., the MCF-7 assay) greater than thatexhibited by 4,4′-(propane-2,2-diyl)bis(2,6-dibromophenol) in the assay,

Embodiment 40

The polymer, coating composition, article, or method of any precedingembodiment wherein one or both of the polymer or the coating compositionare at least substantially free, more preferably essentially free, evenmore preferably essentially completely free, and optimally completelyfree of bound polyhydric phenol compounds, or diepoxides thereof, thatexhibit a degree of estrogen agonist activity, in a competent in vitrohuman estrogen receptor assay (e.g., the MCF-7 assay) greater than thatexhibited by 2,2-bis(4-hydroxyphenyl)propanoic acid in the assay.

Segments of Formula (I) and compounds of Formulas (II) or (III) whereineach of the depicted phenylene groups include one or two ortho R¹ groups(relative to the depicted oxygen atom) are preferred in someembodiments. Below is a table exemplifying some non-limitingcombinations of one or more ortho R¹ and R², if present, for a givenphenylene group. The table is non-limiting with respect to the ringposition of R² (e.g., ortho, meta, para), although typically R², ifpresent, will be located at a para position relative to the oxygen atom.The columns labeled “Ortho Position A” and “Ortho Position B” indicatethe R¹ group present at each ortho position of the phenylene group(assuming R² is not located at an ortho position). Positions “A” or “B”can be either ortho position relative to the depicted oxygen atom. If R²is located at an ortho position of the phenylene group, then the grouplisted in the “Ortho Position B” column is not present. Typically,though not required, the phenylene groups in a given segment of Formula(IA) or compound of Formula (HA) or (IIA) will be “symmetric” relativeto the second phenylene group such that the same ortho group (asdelineated in the ortho position column “A” or “B”) is located on eachring at the same ortho position.

The below table is also intended as a listing of independent examples ofR¹ or R₂, as well as examples of combinations of R¹ and R² (regardlessof whether R¹ is ortho or meta relative to the oxygen atom, whetherother R¹ are present in a particular phenylene group, or whether the oneor more R¹ are the same for both of the phenylene groups).

Ortho Position “A” Ortho Position “B” R² Butyl Hydrogen 2-ButylideneButyl Methyl 2-Butylidene Butyl Ethyl 2-Butylidene Butyl Propyl2-Butylidene Butyl Isopropyl 2-Butylidene Butyl Butyl 2-Butylidene EthylHydrogen 2-Butylidene Ethyl Methyl 2-Butylidene Ethyl Ethyl 2-ButylideneIsopropyl Hydrogen 2-Butylidene Isopropyl Methyl 2-Butylidene IsopropylEthyl 2-Butylidene Isopropyl Propyl 2-Butylidene Isopropyl Isopropyl2-Butylidene Methyl Hydrogen 2-Butylidene Methyl Methyl 2-ButylidenePropyl Hydrogen 2-Butylidene Propyl Methyl 2-Butylidene Propyl Ethyl2-Butylidene Propyl Propyl 2-Butylidene sec-Butyl Hydrogen 2-Butylidenesec-Butyl Methyl 2-Butylidene sec-Butyl Ethyl 2-Butylidene sec-ButylPropyl 2-Butylidene sec-Butyl Isopropyl 2-Butylidene sec-Butyl Butyl2-Butylidene sec-Butyl sec-Butyl 2-Butylidene tert-Butyl Hydrogen2-Butylidene tert-Butyl Methyl 2-Butylidene tert-Butyl Ethyl2-Butylidene tert-Butyl Propyl 2-Butylidene tert-Butyl Isopropyl2-Butylidene tert-Butyl Butyl 2-Butylidene tert-Butyl sec-Butyl2-Butylidene tert-Butyl tert-Butyl 2-Butylidene Butyl Hydrogen ButyleneButyl Methyl Butylene Butyl Ethyl Butylene Butyl Propyl Butylene ButylIsopropyl Butylene Butyl Butyl Butylene Ethyl Hydrogen Butylene EthylMethyl Butylene Ethyl Ethyl Butylene Isopropyl Hydrogen ButyleneIsopropyl Methyl Butylene Isopropyl Ethyl Butylene Isopropyl PropylButylene Isopropyl Isopropyl Butylene Methyl Hydrogen Butylene MethylMethyl Butylene Propyl Hydrogen Butylene Propyl Methyl Butylene PropylEthyl Butylene Propyl Propyl Butylene sec-Butyl Hydrogen Butylenesec-Butyl Methyl Butylene sec-Butyl Ethyl Butylene sec-Butyl PropylButylene sec-Butyl Isopropyl Butylene sec-Butyl Butyl Butylene sec-Butylsec-Butyl Butyiene tert-Butyl Hydrogen Butylene tert-Butyl MethylButylene tert-Butyl Ethyl Butylene tert-Butyl Propyl Butylene tert-ButylIsopropyl Butylene tert-Butyl Butyl Butylene tert-Butyl sec-ButylButylene tert-Butyl tert-Butyl Butylene Butyl Hydrogen Ethylidene ButylMethyl Ethylidene Butyl Ethyl Ethylidene Butyl Propyl Ethylidene ButylIsopropyl Ethylidene Butyl Butyl Ethylidene Ethyl Hydrogen EthylideneEthyl Methyl Ethylidene Ethyl Ethyl Ethylidene Isopropyl HydrogenEthylidene Isopropyl Methyl Ethylidene Isopropyl Ethyl EthylideneIsopropyl Propyl Ethylidene Isopropyl Isopropyl Ethylidene MethylHydrogen Ethylidene Methyl Methyl Ethylidene Propyl Hydrogen EthylidenePropyl Methyl Ethylidene Propyl Ethyl Ethylidene Propyl PropylEthylidene sec-Butyl Hydrogen Ethylidene sec-Butyl Methyl Ethylidenesec-Butyl Ethyl Ethylidene sec-Butyl Propyl Ethylidene sec-ButylIsopropyl Ethylidene sec-Butyl Butyl Ethylidene sec-Butyl sec-ButylEthylidene tert-Butyl Hydrogen Ethylidene tert-Butyl Methyl Ethylidenetert-Butyl Ethyl Ethylidene tert-Butyl Propyl Ethylidene tert-ButylIsopropyl Ethylidene tert-Butyl Butyl Ethylidene tert-Butyl sec-ButylEthylidene tert-Butyl tert-Butyl Ethylidene Butyl Hydrogen MethylideneButyl Methyl Methylidene Butyl Ethyl Methylidene Butyl PropylMethylidene Butyl Isopropyl Methylidene Butyl Butyl Methylidene EthylHydrogen Methylidene Ethyl Methyl Methylidene Ethyl Ethyl MethylideneIsopropyl Hydrogen Methylidene Isopropyl Methyl Methylidene IsopropylEthyl Methylidene Isopropyl Propyl Methylidene Isopropyl IsopropylMethylidene Methyl Hydrogen Methylidene Methyl Methyl Methylidene PropylHydrogen Methylidene Propyl Methyl Methylidene Propyl Ethyl MethylidenePropyl Propyl Methylidene sec-Butyl Hydrogen Methylidene sec-ButylMethyl Methylidene sec-Butyl Ethyl Methylidene sec-Butyl PropylMethylidene sec-Butyl Isopropyl Methylidene sec-Butyl Butyl Methylidenesec-Butyl sec-Butyl Methylidene tert-Butyl Hydrogen Methylidenetert-Butyl Methyl Methylidene tert-Butyl Ethyl Methylidene tert-ButylPropyl Methylidene tert-Butyl Isopropyl Methylidene tert-Butyl ButylMethylidene tert-Butyl sec-Butyl Methylidene tert-Butyl tert-ButylMethylidene Butyl Hydrogen Propylidene Butyl Methyl Propylidene ButylEthyl Propylidene Butyl Propyl Propylidene Butyl Isopropyl PropylideneButyl Butyl Propylidene Ethyl Hydrogen Propylidene Ethyl MethylPropylidene Ethyl Ethyl Propylidene Isopropyl Hydrogen PropylideneIsopropyl Methyl Propylidene Isopropyl Ethyl Propylidene IsopropylPropyl Propylidene Isopropyl Isopropyl Propylidene Methyl HydrogenPropylidene Methyl Methyl Propylidene Propyl Hydrogen Propylidene PropylMethyl Propylidene Propyl Ethyl Propylidene Propyl Propyl Propylidenesec-Butyl Hydrogen Propylidene sec-Butyl Methyl Propylidene sec-ButylEthyl Propylidene sec-Butyl Propyl Propylidene sec-Butyl IsopropylPropylidene sec-Butyl Butyl Propylidene sec-Butyl sec-Butyl Propylidenetert-Butyl Hydrogen Propylidene tert-Butyl Methyl Propylidene tert-ButylEthyl Propylidene tert-Butyl Propyl Propylidene tert-Butyl IsopropylPropylidene tert-Butyl Butyl Propylidene tert-Butyl sec-ButylPropylidene tert-Butyl tert-Butyl Propylidene Butyl Hydrogen1-phenylethylidene Butyl Methyl 1-phenylethylidene Butyl Ethyl1-phenylethylidene Butyl Propyl 1-phenylethylidene Butyl Isopropyl1-phenylethylidene Butyl Butyl 1-phenylethylidene Ethyl Hydrogen1-phenylethylidene Ethyl Methyl 1-phenylethylidene Ethyl Ethyl1-phenylethylidene Isopropyl Hydrogen 1-phenylethylidene IsopropylMethyl 1-phenylethylidene Isopropyl Ethyl 1-phenylethylidene IsopropylPropyl 1-phenylethylidene Isopropyl Isopropyl 1-phenylethylidene MethylHydrogen 1-phenylethylidene Methyl Methyl 1-phenylethylidene PropylHydrogen 1-phenylethylidene Propyl Methyl 1-phenylethylidene PropylEthyl 1-phenylethylidene Propyl Propyl 1-phenylethylidene sec-ButylHydrogen 1-phenylethylidene sec-Butyl Methyl 1-phenylethylidenesec-Butyl Ethyl 1-phenylethylidene sec-Butyl Propyl 1-phenylethylidenesec-Butyl Isopropyl 1-phenylethylidene sec-Butyl Butyl1-phenylethylidene sec-Butyl sec-Butyl 1-phenylethylidene tert-ButylHydrogen 1-phenylethylidene tert-Butyl Methyl 1-phenylethylidenetert-Butyl Ethyl 1-phenylethylidene tert-Butyl Propyl 1-phenylethylidenetert-Butyl Isopropyl 1-phenylethylidene tert-Butyl Butyl1-phenylethylidene tert-Butyl sec-Butyl 1-phenylethylidene tert-Butyltert-Butyl 1-phenylethylidene Butyl Hydrogen Diphenylmethylidene ButylMethyl Diphenylmethylidene Butyl Ethyl Diphenylmethylidene Butyl PropylDiphenylmethylidene Butyl Isopropyl Diphenylmethylidene Butyl ButylDiphenylmethylidene Ethyl Hydrogen Diphenylmethylidene Ethyl MethylDiphenylmethylidene Ethyl Ethyl Diphenylmethylidene Isopropyl HydrogenDiphenylmethylidene Isopropyl Methyl Diphenylmethylidene Isopropyl EthylDiphenylmethylidene Isopropyl Propyl Diphenylmethylidene IsopropylIsopropyl Diphenylmethylidene Methyl Hydrogen Diphenylmethylidene MethylMethyl Diphenylmethylidene Propyl Hydrogen Diphenylmethylidene PropylMethyl Diphenylmethylidene Propyl Ethyl Diphenylmethylidene PropylPropyl Diphenylmethylidene sec-Butyl Hydrogen Diphenylmethylidenesec-Butyl Methyl Diphenylmethylidene sec-Butyl Ethyl Diphenylmethylidenesec-Butyl Propyl Diphenylmethylidene sec-Butyl IsopropylDiphenylmethylidene sec-Butyl Butyl Diphenylmethylidene sec-Butylsec-Butyl Diphenylmethylidene tert-Butyl Hydrogen Diphenylmethylidenetert-Butyl Methyl Diphenylmethylidene tert-Butyl EthylDiphenylmethylidene tert-Butyl Propyl Diphenylmethylidene tert-ButylIsopropyl Diphenylmethylidene tert-Butyl Butyl Diphenylmethylidenetert-Butyl sec-Butyl Diphenylmethylidene tert-Butyl tert-ButylDiphenylmethylidene

TEST METHODS

Unless indicated otherwise, the following test methods were utilized inthe Examples that follow.

Differential Scanning Calorimetry

Samples for differential scanning calorimetry (“DSC”) testing wereprepared by first applying the liquid resin composition onto aluminumsheet panels. The panels were then baked in a Fisher Isotemp electricoven for 20 minutes at 300° F. (149° C.) to remove volatile materials.After cooling to room temperature, the samples were scraped from thepanels, weighed into standard sample pans and analyzed using thestandard DSC heat-cool-heat method. The samples were equilibrated at−60° C., then heated at 20° C. per minute to 200° C., cooled to −60° C.,and then heated again at 20° C. per minute to 200° C. Glass transitionswere calculated from the thermogram of the last heat cycle. The glasstransition was measured at the inflection point of the transition.

Adhesion

Adhesion testing is performed to assess whether the coating adheres tothe coated substrate. The adhesion test was performed according to ASTMD 3359—Test Method B, using SCOTCH 610 tape (available from 3M Companyof Saint Paul, Minn.). Adhesion is generally rated on a scale of 0-10where a rating of “10” indicates no adhesion failure, a rating of “9”indicates 90% of the coating remains adhered, a rating of “8” indicates80% of the coating remains adhered, and so on. Adhesion ratings of 10are typically desired for commercially viable coatings.

Blush Resistance

Blush resistance measures the ability of a coating to resist attack byvarious solutions. Typically, blush is measured by the amount of waterabsorbed into a coated film. When the film absorbs water, it generallybecomes cloudy or looks white. Blush is generally measured visuallyusing a scale of 0-10 where a rating of “10” indicates no blush and arating of “0” indicates complete whitening of the film. Blush ratings ofat least 7 are typically desired for commercially viable coatings andoptimally 9 or above.

Corrosion

Corrosion is a measure of a coatings ability to resist acorrosive/acidic environment. It is generally measured on a scale of0-10. A “0” indicates the coating is completely corroded, observed bybubbling or blistering of the film in all areas. A “10” indicates thecoating is unchanged from before it was subjected to the corrosiveenvironment.

Stain

Stain is a measure of a coating's ability to resist staining by a media.It is generally measured on a scale of 0-10. A “0” indicates that thecoating is completely stained with a complete color change of the filmobserved in all areas. A “10” indicates that the coloration of thecoating is unchanged from before it was subjected to the stainingenvironment.

Pencil Hardness

This test measures the hardness of a cured coating. Pencil hardness wasassessed using ASTM D3363, with the test run against metal grain. Thedata is reported in the form of the last successful pencil prior to filmrupture. Thus, for example, if a coating does not rupture when testedwith a 2H pencil, but ruptures when tested with a 3H pencil, the coatingis reported to have a pencil hardness of 2H.

Metal Exposure

This test measures the ability of a coated substrate to retain itsintegrity as it undergoes the formation process necessary to produce afabricated article such as a riveted beverage can end. It is a measureof the presence or absence of cracks or fractures in the formed end. Theend is typically placed on a cup filled with an electrolyte solution.The cup is inverted to expose the surface of the end to the electrolytesolution. The amount of electrical current that passes through the endis then measured. If the coating remains intact (no cracks or fractures)after fabrication, minimal current will pass through the end.

For the present evaluation, fully converted riveted 202 standard openingbeverage ends were exposed for a period of approximately 4 seconds to aroom-temperature electrolyte solution comprised of 1% NaCl by weight indeionized water. The coating evaluated was present on the interiorsurface of the beverage end. Metal exposure was measured using a WACOEnamel Rater II (available from the Wilkens-Anderson Company, Chicago,Ill.) with an output voltage of 6.3 volts. The measured electricalcurrent, in milliamps, is reported. End continuities were testedinitially and then after the ends were subjected to a boiling Dowfaxdetergent solution (0.19% in deionized water, the Dowfax 2A1 product isavailable from Dow Chemical) for 60 minutes. After cooling and drying,the milliamps of current passing through the end was measured again.

Preferred coatings of the present invention initially pass less than 10milliamps (mA) when tested as described above, more preferably less than5 mA, most preferably less than 2 mA, and optimally less than 1 mA.After Dowfax, preferred coatings give continuities of less than 20 mA,more preferably less than 10 mA, and even more preferably less than 5mA.

Solvent Resistance

The extent of “cure” or crosslinking of a coating is measured as aresistance to solvents, such as methyl ethyl ketone (MEK) (availablefrom Exxon, Newark, N.J.). This test is performed as described in ASTM D5402-93. The number of double-rubs (i.e., one back- and forth motion) isreported. This test is often referred to as “MEK Resistance.”

Initial Metal Exposure

This test method determines the amount the inside surface of a can thathas not been effectively coated by the sprayed coating in an “insidespray” application. This determination is made through the use of anelectrolyte solution (1% NaCl in deionized water). The interior “insidespray” coating is typically applied using a high pressure airless spray.The following film weights are typically used: 1.0 msi for a beer can,1.5 msi for a soda can, and 2.2 msi for a can intended for use inpackaging a “hard-to-hold” product. A typical cure condition would be aminimum bake for 30 minutes at 370° F. (390° F. peak on center dome ofcan).

The inside spray coated can is filled with this electrolyte solution,and an electrical probe is attached in contact to the outside of the can(uncoated, electrically conducting). A second probe is immersed in theelectrolyte solution in the middle of the inside of the can. If anyuncoated metal is present on the inside of the can, a current is passedbetween these two probes and registers as a value on an LED display. TheLED displays the conveyed currents in milliamps (mA). The current thatis passed is directly proportional to the amount of metal that has notbeen effectively covered with coating. The goal is to achieve 100%coating coverage on the inside of the can, which would result in an LEDreading of 0.0 mA. Preferred “inside spray” coatings give metal exposurevalues of less than 3 mA, more preferred values of less than 2 mA, andeven more preferred values of less than 1 mA.

Metal Exposure after Drop can Damage

Drop can damage resistance measures the ability of the coated food orbeverage can to resist cracks after being subjected to conditionssimulating dropping of a filled can. The presence of cracks is measuredby passing electrical current via an electrolyte solution, as previouslydescribed in the Initial Metal Exposure section. A food or beverage cancoated on the interior with the coating to be tested is filled with anelectrolyte solution (1% NaCl in deionized water) and the initial metalexposure is recorded. The electrolyte solution is removed and the can isfilled with room-temperature tap water. For two-piece “inside spray”cans, the film weights described in the Initial Metal Exposure test canbe used.

The filled can, which does not include a “top” can end, is droppedthrough a cylindrical tube having a 2 and ⅞ inch internal diameter, canbottom down, onto an impact wedge (e.g., an inclined plane angledupwards at 45 degrees). The impact wedge is positioned relative to thetube such that a dent is formed in the rim area where the can bottom endmeets the sidewall (typically referred to as the “chime” of a beveragecan). The can is dropped from a height of 24 inches as measured betweenthe can bottom and the point of impact on the impact wedge. The can isthen turned 180 degrees, and the process is repeated. Water is thenremoved from the can and metal exposure is again measured as describedabove. If there is no damage to the coating, no change in current (mA)will be observed relative to the Initial Metal Exposure value.Typically, an average of at least 5 container runs is recorded. Bothmetal exposures results before and after the drop are reported. Thelower the milliamp value, the better the resistance of the coating todrop damage. Preferred coatings give metal exposure values after dropcan damage testing of less than 3.5 mA, more preferred valued of lessthan 2.5 mA, and even more preferred values of less than 1.5 mA.

EXAMPLES

The following examples are offered to aid in understanding of thepresent invention and are not to be construed as limiting the scopethereof. Unless otherwise indicated, all parts and percentages are byweight. The constructions cited were evaluated by tests as follows:

Example 1: Diepoxides of Ortho-Substituted Dihydric Phenols Run I:Diglycidyl ether of 4,4′-methylenebis(2,6-di-tert-butylphenol)

A solution of 4,4′-methylenebis(2,6-di-t-butylphenol) (500 grams, 1.076moles obtained from Albemarle Corporation) in anhydrousdimethylformamide (1.5 liters) was cooled to −10° C. and a solution ofsodium tert-pentoxide (374 grams, 3.23 moles) in anhydrousdimethylformamide (1.5 liters) was added drop wise at −10 to −5° C. Themixture was stirred for 30 minutes at −10° C. Epichlorohydrin (1.9liters, 24.2 moles) was added via dropping funnel at −10 to −5° C. Thesolution was allowed to warm up to room temperature and then was heatedfor 16 hours at a temperature of from 75 to 82° C. After cooling down toambient temperature, the mixture was added to cold tap water (12liters). Ethyl acetate (5 liters) was added to the mixture, which wasstirred for 10 minutes and separated. The aqueous layer was extractedagain with additional ethyl acetate (3 liters). The combined ethylacetate extracts were washed twice with brine (2×6 liters), dried overanhydrous sodium sulfate (600 grams), and filtered. The solvent wasremoved under reduced pressure to give 887 grams of crude product as apurple oil. The crude product was dissolved in toluene (600 milliliters)and passed over a silica gel pad (1.4 kilograms), and eluted with amixture of toluene and heptane (8 parts toluene to 2 parts heptane). Thefractions containing product were combined and evaporated under reducedpressure. The product was mostly the desired diepoxide (756 grams,yellow oil which crystallizes in time), with some monoepoxide present.The purified material (756 grams) was dissolved at 70° C. in 2-propanol(2.3 liters) and then allowed to cool down to room temperatureovernight. The flask was kept in an ice-water bath for 3 hours, filteredand the solids were washed three times with cold 2-propanol (3×400milliliters). The obtained solid was dried under high vacuum at ambienttemperature to give the final product as a white solid (371 grams havingan HPLC purity of 95.2%, and a yield of 60%). The epoxy value of thefinal product was 0.367 equivalents per 100 grams. The resultingdiglycidyl ether of 4,4′-methylenebis(2,6-di-t-butylphenol) was testedusing suitable genotoxicity assays (e.g., Ames II assay) and was foundto be non-genotoxic.

Run II: Diglycidyl Ether 4,4′Butylidenebis(2-t-butyl-5-methylphenol)

A 20-gram batch of the diglycidyl ether of4,4′-butylidenebis(2-t-butyl-5-methylphenol) was prepared by reactingepichlorohydrin with 4,4′-butylidenebis(2-t-butyl-5-methylphenol).Multiple purification steps were required to obtain a suitably purebatch. The purified batch exhibited an epoxy value of 0.402 equivalentsper 100 grams. The resulting diglycidyl ether of4,4′-butylidenebis(2-t-butyl-5-methylphenol) was tested using suitablegenotoxicity assays (e.g., Ames II assay) and was found to benon-genotoxic.

Run III: Diglycidyl Ether of 4,4′-methylenebis(2,6-dimethylphenol)

4,4′-Methylenebis(2,6-dimethylphenol) (32 grams, 0.125 moles),epichlorohydrin (140 milliliters, 1.79 moles), and 2-propanol (150milliliters) were heated to 80° C. in an oil bath. Sodium hydroxide(12.5 grams, 0.313 moles) in water (20 milliliters) was added inportions over 5 minutes. The purple solution was heated for 2 hours at80° C. The mixture was cooled to room temperature, filtered, andconcentrated on a rotary evaporator at a temperature of about 30-40° C.The remaining oil was mixed with dichloromethane (50 milliliters) andheptane (100 milliliters) and allowed to stir for 30 minutes at ambienttemperature. The salts were removed by filtration and the filtrate wasconcentrated on a rotary evaporator at 30-40° C. The remaining oil wasdried under high vacuum at ambient temperature until a constant weightwas obtained. The crude product was crystallized twice from methanol(250 milliliters) and dried under high vacuum at ambient temperatureuntil a constant weight was obtained. The experiment generateddiglycidyl ether of 4,4′-methylenebis(2,6-dimethylphenol) (28 grams, 60%yield) as a white solid. The epoxy value was 0.543 equivalents per 100grams.

Example 2: Dihydric Phenol Adducts Run I: Dihydric Phenol Adduct of 1Mole 4,8-Bis(hydroxymethyl)tricyclo[5.2.1.0]decane with 2 moles of3-hydroxy benzoic acid

To a 4-neck round-bottom flask equipped with a mechanical stirrer, awater-cooled condenser on top of a Dean-Stark Trap, and a thermocoupleconnected to heating control device and a heating mantle was added249.24 parts of tricyclodecane dimethanol or “TCDM” (from OXEA), 350.76parts of 3-hydroxybenzoic acid (from Aldrich), and 0.6 parts of apolymerization catalyst Stirring and heating was begun over 4 hoursuntil the batch reached 230° C. The batch was heated at 230° C. for 4more hours, at which time about 43 parts of water was collected and theacid value was 2.0 mg KOH/gram. At that time, heating was discontinueduntil the batch reached 120° C., at which time the batch was discharged.The material was a solid at room temperature that could be broken up.

Run II: Dihydric Phenol Adduct of 1 Mole4,8-Bis(hydroxymethyl)tricyclo[5.2.1.0]decane with 2 Moles of 4-hydroxyphenylacetic acid

To a 4-neck round-bottom flask equipped with a mechanical stirrer, awater-cooled condenser on top of a Dean-Stark Trap, and a thermocoupleconnected to heating control device and a heating mantle was added 235.3parts of TCDM (from OXEA), 364.7 parts of 4-hydroxy phenyl acid (fromAceto), and 0.65 parts of polymerization catalyst. Stirring and heatingwas begun over 7 hours until the batch reached 230° C. The batch washeated at 230° C. for 8 more hours, at which time a total of 40 parts ofwater were collected and the acid value was 1.8 mg KOH/gram. At thattime, heating was discontinued until the batch reached 120° C., at whichtime the batch was discharged. The material was a tacky semisolid atroom temperature.

Run III: Dihydric Phenol Adduct of 1 Mole 1,4-Cyclohexanedimethanol(CHDM) with 2 Moles of 3-hydroxy benzoic acid

To a 4-neck round-bottom flask equipped with a mechanical stirrer, awater-cooled condenser on top of a Dean-Stark Trap, and a thermocoupleconnected to heating control device and a heating mantle was added 228.6parts of the CHDM-90 product (90% cyclohexane dimethanol in water fromEastman), 394.2 parts of 3-hydroxybenzoic acid (from Aceto), and 0.6parts polymerization catalyst. Stirring and heating was begun over 4hours until the batch reached 230° C. The batch was heated at 230° C.for 8 more hours, at which time 70 parts of water were collected and theacid value was 1.6 mg KOH/gram. At that time, heating was discontinueduntil the batch reached 120° C., at which time the batch was discharged.The material was a solid at room temperature that could be broken up.

Run IV: Dihydric Phenol Adduct of 1 mole 1,4-Cyclohexanedimethanol(CHDM) with 2 Moles of 4-hydroxy phenylacetic acid

To a 4-neck round-bottom flask equipped with a mechanical stirrer, awater-cooled condenser on top of a Dean-Stark Trap, and a thermocoupleconnected to heating control device and a heating mantle was added 214.3parts of the CHDM-90 product, 407.1 parts of 4-hydroxy phenylacetic acid(from Aceto), and 0.6 parts polymerization catalyst. Stirring andheating was begun over 4 hours until the batch reached 230° C. The batchwas heated at 230° C. for 6 more hours, at which time 65 parts of waterwere collected and the acid value was 3.0 mg KOH/gram. At this time,heating was discontinued until the batch reached 120° C., at which timethe batch was discharged. The material was a solid at room temperaturethat could be broken up.

Example 3: Polyether Polymers

As indicated in the below Table 1, 15 different polyether polymers(i.e., Runs 1 to 15) were made by upgrading various diepoxides (“DGE” inTable 1) of Example 1 with various dihydric phenols of Example 2.

The following general procedure was used to prepare each of thepolyether polymers of Runs 1-15 in Table 1: To a 4-neck round-bottomflask equipped with a mechanical stirrer, a water-cooled condenser, anda thermocouple connected to heating control device and a heating mantlewas added a specified amount of a diepoxide of Example 1, a specifiedamount of a dihydric phenol of Example 2 or hydroquinone, 0.1% partsCATALYST 1201 polymerization catalyst (from Shell), and an amount ofmethylisobutylketone (from Ashland) suitable to take the batch to 95wt-% solids. Stirring and heating was begun until the batch becamehomogeneous and reached the temperature indicated Table 1. The batch washeld at that temperature until the target epoxy value (“EV”) wasreached. At that time, heating was discontinued and cyclohexanone (fromAshland) was slowly added until the weight percent solids (or weightpercent nonvolatile material) indicated in Table 1 was achieved. Thebatch was discharged when the temperature was below 70° C. As indicatedin the below Table 1, all of polymers Runs 1-10 exhibited good molecularweight build and a high Tg.

The aforementioned methodology can also be used to formulate polyetherpolymers using the diepoxides of Example 1, Runs II, III, and IV.

TABLE 1 Reaction Ex. 1 Weight Dihydric Weight Temp Target Act. Tg RunDGE Parts Phenol Parts (° C.) EV EV NV** Mn Mw (° C.) 1 Run I 45.3 Ex.2, 29.7 120 0.036 0.036 45.6 4280 10780 91 Run I 2 Run I 44.3 Ex. 2,30.7 120 0.036 0.034 41.7 4240 15680 82 Run II 3 Run I 47.4 Ex. 2, 27.6120 0.036 0.032 40.4 5200 15330 94 Run III 4 Run I 46.2 Ex. 2, 28.8 1200.036 0.034 43.3 5560 17800 82 Run IV 5 Run I 46 Ex. 2, 29 120 0.02 0.1830.9 7380 29540 99 Run III 6 Run I 45.2 Ex. 2, 29.8 120 0.01 0.007 31.25870 28620 97 Run III 7 Run I 145.4 Ex. 2, 94.6 120 0.032 0.032 42.85230 14970 80 Run IV 8 Run I 142.3 Ex. 2, 97.7 120 0.021 0.021 41.9 646026900 82 Run IV 9 Run I 203 HQ* 36.96 160 0.032 0.032 40.8 4700 10650100 10 Run I 201.8 HQ* 38.2 160 0.021 0.019 40.4 6100 14280 105 11 RunII 339.2 HQ* 60.8 160 0.028 0.029 40.8 5700 13280 98 12 Run II 244.5 Ex.2, 155.5 130 0.028 0.027 41.0 3800 8320 82 Run IV 13 Run II 250.8 Ex. 2,149.2 130 0.028 0.028 40.8 6130 17570 91 Run III 14 Run III 63.2 HQ*16.8 160 0.035 0.033 39.3 5400 12900 95 15 Run III 41.9 Ex. 2, 38.1 1300.029 0.023 42.2 7600 48900 90 Run III *HQ stands for hydroquinone. **NVstands for wt-% non-volatile material

Example 4: Coating Compositions

The polyether polymer composition of Example 3, Run 2 and Example 3, Run4 were each cut to a non-volatile content of 35 wt-% usingcyclohexanone. Then 20 wt-% (solids on solids) of phenolic crosslinkerwas added, followed by 0.1 wt-% H₃PO₄ (solids on solids) added as a 10%solution in butanol. Thus, were provided two acid-catalyzed 80:20polyether:phenolic formulations. The coating composition formulatedusing Example 3, Run 2 is referred to herein as Example 4, Run 1,whereas the coating composition formulated using Example 3, Run 4 isreferred to herein as Example 4, Run 2.

Example 5: Coated Substrate

The two coating compositions above, along with an industry standardBPA-based polyether coating composition, were each applied to both 75#tinplate (ETP) and tin-free steel (TFS). The coatings were drawn downwith the appropriate-sized wire bars to obtain coatings having adry-film thickness of 4.5-5.0 milligrams/square-inch (msi). The coatedmetal samples were then baked for 12 minutes in a 403° F. (˜206° C.)gas-fired oven. 202 sanitary food can ends were formed from theresulting coated plates. Each can end was given a 14-inch-pound reverseimpact in the center of the uncoated side of the can end. The can endswere then immersed in two different aggressive food products (i.e.,Aggressive Food Products 1 and 2 in Table 2) having an initialtemperature of 180° F. (82° C.) and stored for 2 weeks at 120° F. (˜49°C.). After 2 weeks, the can ends were removed from the food product,rinsed with water, and evaluated for adhesion, corrosion, stain, andblush. The results are shown in Table 2 below. The coating compositionsof Example 4 exhibited coating properties equal to or better than thatof the industry standard epoxy coating

TABLE 2 Coating Commercial Example 4, Example 4, Composition Control Run1 Run 2 ETP Aggresive Food Product 1 Adhesion/Blush 10/10 10/10 10/10Stain/Corrosion 10/10 10/10 10/10 Aggressive Food Product 2Adhesion/Blush 10/10 10/10 10/10 Stain/Corrosion 10/10 10/10 10/10 TFSAggresive Food Product 1 Adhesion/Blush 10/10 10/10 10/10Stain/Corrosion 10/10 10/10 10/10 Aggressive Food Product 2Adhesion/Blush 10/10 10/10 10/10 Stain/Corrosion 10/9  10/10 10/10

Example 6: Water-Dispersible polyether Polymers Run 1

To a 4-neck round-bottom flask equipped with a mechanical stirrer, anitrogen inlet to maintain a nitrogen blanket, a water-cooled condenser,and a thermocouple connected to heating control device and a heatingmantle was added 65.34 parts of the diepoxide of Example 1, Run III(i.e., the diglycidyl ether of 4,4′-methylenebis(2,6-dimethylphenol),17.61 parts of hydroquinone, 0.054 parts CATALYST 1201 catalyst (fromShell), 0.305 parts sorbic acid, and 1.96 parts ethyl carbitol. Thismixture was heated with stirring to 125° C., allowed to exotherm to 152°C., then heated at 155° C. for 4 hours until the epoxy value was 0.025eq/100 g. A water-dispersible polymer was then produced using a mixtureof styrene, ethyl acrylate, methylmethacrylate, acrylic acid, andmethacrylic acid pursuant to the teachings of U.S. Pat. No. 5,830,952,with the above polyether polymer used in place of the polyether polymertaught in U.S. Pat. No. 5,830,952. The water-dispersible polymer yieldeda water-based dispersion having a nonvolatile content of about 40% andan acid value of 15-45 mg KOH/gram.

The resin was formulated into an aqueous finish in the same fashion as acommercial epoxy polymer based on BPA and BADGE and baked onchrome-treated aluminum substrate for 60 seconds at 465° F. (241° C.) toa dry film thickness of 7 msi. The properties of the cured coatingincluding the Example 6, Run 1 resin were similar to that of thecommercial epoxy control coating. Table 3 below illustrates some of thecoating properties of the Example 6, Run 1 coating relative to thecontrol coating.

TABLE 3 Metal Exposure (milliamps) Before After DI Water Retort MEKBoiling Boiling Blush Adh. Double Pencil Coating Dowfax Dowfax (W/V)*(W/V)* Rubs Hardness BADGE/BPA 0.2 0.9 10/10 10/10 20-50 4H ControlExample 6, Run 1 0.1 3.1 10/10 10/10 20-50 3H *Strips of coated aluminumwere placed in a pressure cooker filled with deionized water andprocessed for 90 minutes at 250° F. (121° C.). Afterward, the coatedstrips were rated for blush and adhesion both in the area where thecoated strip was immersed in the liquid (“W”) and where the area of thestrip was in the vapor phase (“V”).

Run 2

To a 4-neck round-bottom flask equipped with a mechanical stirrer, anitrogen inlet to maintain a nitrogen blanket, a water-cooled condenser,and a thermocouple connected to heating control device and a heatingmantle was added 59.96 parts of the diepoxide of Example 1, Run II(i.e., the diglycidyl ether of4,4′-butylidenebis(2-t-butyl-5-methylphenol)), 39.8 parts of the Example2, Run 3 dihydric phenol adduct of CHDM and 3-HBA, 0.08 parts CATALYST1201 catalyst, and 2.22 parts xylene. This mixture was stirred andheated to 130° C. and held for 3 hours, at which time the epoxy valuewas 0.034 equivalents per 100 grams. 25.05 parts of butyl cellosolvewere added, followed by 10.53 parts primary amyl alcohol and 14.47 partsn-butanol while the temperature was stabilized at 120° C. A premixtureof methacrylic acid, styrene, and benzoyl peroxide was then added whilemaintaining the temperature. At the end of the addition, the additiondevice was flushed with butyl cellosolve. After holding at temperaturefor 2 hours after the end of the feed, deionized water was added and thetemperature was stabilized at 90° C. A room-temperature premix ofdeionized water and dimethylethanol amine was added over time and thebatch was held, followed by subsequent additions of deionized water. Theresulting water-based dispersion had a nonvolatile content of about 20%and an acid value of 80-120 mg KOH/gram.

A finish was made by mixing the water-based resin of Example 6, Run 2with a solution consisting of suitable amounts of phenol-based phenolicresin, t-butyl-phenol-based phenolic resin, and organic solvent. Thiswas followed by an additional let-down of organic solvent and deionizedwater to yield a spray coating having a #4 Ford cup viscosity of 20seconds and a nonvolatile content of about 20%. This water-based finishwas sprayed on the interior of drawn and ironed ETP food cans and bakedfor 3.5 minutes at 425° F. (218° C.), yielding a cured coating having adry film weight of 275 milligrams per can. When tested against a similarBADGE/BPA-based control coating, the coating properties of the coatingformulated using the Example 6, Run 2 resin were similar, includingcorrosion resistance.

Example 7: Preparation of Solid Resin from Advancement of DiglycidylEther with Hydroquinone

A reaction flask equipped with a mechanical stirrer, thermocouple,nitrogen inlet and vacuum outlet was charged with 900.0 parts of thediglycidyl ether described in Example 1, Run II, having a titrated epoxyvalue of 0.376 (epoxide equivalent weight=0.266) (3.383 equivalents).The contents were gently heated under nitrogen blanket until completelymelted, then agitation was started and 0.80 parts ofethyltriphenylphosphonium iodide catalyst were added, followed by 124.0parts of hydroquinone (2.252 equivalents). Heating was continued under areduced pressure of approximately 50 torr (to reduce the level ofresidual moisture or other volatiles) to a temperature of 130° C., thenheating was continued under atmospheric pressure. When the temperaturereached 140° C., external heating was discontinued and the reaction wasallowed to exotherm. Over a period of approximately 25 minutes, thereaction temperature increased to a peak exotherm temperature of 181° C.The contents were held for an additional 90 minutes at 180° C., thendischarged to shallow aluminum pans and allowed to cool to form afriable solid. The product gave a titrated epoxide equivalent weight of952 (theoretical target=907), and a melt viscosity of 19.3 P (150° C.,900 RPM, Brookfield CAP 2000).

Example 8: Preparation of the bis(3-hydroxybenzoate) ofCyclohexanedimethanol

A reaction flask equipped with mechanical stirrer, thermocouple,nitrogen inlet, and a Dean-Stark trap under a reflux condenser wascharged with 259.6 parts of 1,4-cyclohexanedimethanol (CHDM, 1.8 mol).Agitation was started under a nitrogen blanket, and 497.2 parts of3-hydroxybenzoic acid (3.6 mol), 3.4 parts of p-toluenesulfonic acidmonohydrate (0.018 mol), and 200 parts of xylene were successivelyadded. The contents were heated gradually to reflux and the water ofesterification was collected as a lower layer in the Dean-Stark trap.After approximately 12 hours at 145-150° C., approximately 94% of thetheoretical quantity of water had been collected, and additionalcollection of water in the trap had ceased. The bulk of the xylene wasremoved at ambient pressure, and then vacuum was gradually applied whileholding the product at 150° C. When only minimal evolution of volatileswas observed at approximately 50 torr, the product was discharged into ashallow aluminum pan and allowed to cool to ambient temperature.

Example 9: Preparation of Solid Resin from Advancement of DiglycidylEther with the bis(3-hydroxybenzoate) of CHDM

A reaction flask equipped with mechanical stirrer, thermocouple,nitrogen inlet, and vacuum outlet was charged with 750.0 parts of thediglycidyl ether described in Example 1, Run II having a titrated epoxyvalue of 0.376 (epoxide equivalent weight=266) (2.819 epoxideequivalents), followed by 315.0 parts of the bis(3-hydroxybenzoate) ofCHDM which was prepared according to the procedure of Example 8(calculated theoretical phenolic equivalent weight of 192.2) (1.639equivalents), and 1.30 parts of ethyltriphenylphosphonium iodidecatalyst. The contents were gradually heated until fully melted at about90° C., then agitation was started and the pressure was reduced toapproximately 50 torr in order to remove residual volatiles. Heating wascontinued to a temperature of 140° C., at which point external heatingwas discontinued. The reaction was allowed to exotherm, and the vacuumwas broken once the temperature reached 145° C. The exotherm continuedover the course of approximately 30 minutes to a peak temperature of158° C. The temperature set-point was increased to 160° C. and theproduct was held for an additional 2 hours before discharge. The finalproduct gave a titrated epoxide equivalent weight of 1016 (theoreticaltarget 903) and a melt viscosity of 39.0 P (150° C., 900 RPM, BrookfieldCAP 2000).

Examples 10-12: Preparation of Powder Coatings

The solid resins from Examples 7 and 9 were broken into smaller flakesize using a high-intensity paddle mixer (Reos Inc., Cleveland. Ohio)for two cycles of 10 seconds each at approximately 1,000revolutions-per-minute (“RPM”). The resins were then combined with theadditional ingredients listed in Table 4. The composition shown inExample 10 is a comparative example based upon a conventionalcommercially available BPA-based epoxy resin. All quantities in Table 4are expressed in parts by weight.

TABLE 4 Comparative Example Example Ingredient Example 10 11 12 Epon2004 900.0 Epoxy Upgrade 900.0 from Example 7 Epoxy Upgrade 900.0 fromExample 9 DYHARD 100S 27.0 27.0 27.0 2-methylimidazole 2.0 2.0 2.0 ESCAT60 10.0 10.0 10.0 RESIFLOW PF-67 13.0 13.0 13.0 R2899 Red Iron Oxide42.0 42.0 42.0 VANSIL W-20 325.0 325.0 325.0

Further explanation of certain ingredients included in Table 4 isprovided below. EPON 2004 is a conventional BPA-based epoxy resinavailable from Hexion, Columbus, Ohio Dyhard 100S is a micronized gradeof dicyandiamide treated with silica dry flow agent, available fromAlzchem, Trostberg, Germany. Dyhard MI is a micronized form of2-methylimidazole available from Alzchem. Resiflow PF-67 is apolyacrylate flow control agent available from Estron Chemical, CalvertCity, Ky. Escat 60 is an alkyl imidazole on a silica carrier, availablefrom Estron chemical, Calvert City, Ky. R2899 Red Iron Oxide wasobtained from Rockwood Pigments, Beltsville, Md. Vansil W-20 is awollastonite pigment available from R.T. Vanderbilt Company, Norwalk,Conn.

The ingredients in Table 4 were dry blended in a Reos high-intensitypaddle mixer for two cycles often seconds each at approximately 1000RPM. After dry blending, the samples were extruded in a Coperion ZSK-30extruder operating at approximately 200 RPM with temperature set pointsof 90° C. in zone 1 and 110° C. in zone 2. The extrudate was dischargedthrough chilled rollers, and the resulting solid flake was ground in aMikropul Bantam laboratory mill and then sieved through a 94 meshscreen.

Samples of the finished powder coatings were electrostatic sprayed atapproximately 70 kilovolts onto 0.5 mm thick cold rolled steel panelsand baked for 30 minutes at 220° C. Film properties were as shown inTable 5. The test method for impact resistance can be found in ASTMD2794.

TABLE 5 Comparative Example Example Test Example 10 11 12 Adhesion 9 910 Pencil Hardness 3H 3H 3H Impact Resistance 80 inch- 80 inch- 80 inch-(direct) pounds pounds pounds Solvent Resistance 50 20 50 (MEK DoubleRubs)

Example 13: Powder Coasting Composition

The powder compositions as described in Examples 10-12 are repeatedexcept the dicyandiamide is increased to 36 parts and the acceleratorsare replaced with triphenyl phosphine.

Example 14: Powder Coating Composition

The powder compositions as described in Examples 10-12 are repeatedexcept the dicyandiamide is increased to 36 parts and the acceleratorsare replaced with Curezol C17Z accelerator (available from Air Products,Allentown, Pa.).

Example 15: Synthesis of the diglycidyl ether of4,4′-(1,4-Phenylenebis(propane-2,2-diyl)diphenol and a Polyether PolymerTherefrom

4,4′-(1,4-Phenylenebis(propane-2,2-diyl))diphenol (51.3 grams, 0.125moles), epichlorohydrin (140 milliliters, 1.79 moles), and 2-propanol(150 milliliters) is heated to 80° C. in an oil bath. Sodium hydroxide(12.5 grams, 0.313 moles) in water (20 milliliters) is added in portionsover 5 minutes. The solution is heated for 2 hours at 80° C. The mixtureis cooled to room temperature, filtered, and concentrated on a rotaryevaporator at a temperature of about 30-40° C. The remaining oil ismixed with dichloromethane (50 milliliters) and heptane (100milliliters) and allowed to stir for 30 minutes at ambient temperature.The salts are removed by filtration and the filtrate is concentrated ona rotary evaporator at 30-40° C. The remaining oil is dried under highvacuum at ambient temperature until a constant weight is obtained. Theexperiment is expected to generate the diglycidyl ether of4,4′-(1,4-Phenylenebis(propane-2,2-diyl))diphenol (34 grams, 60% yield).The epoxy value is expected to be about 0.44 equivalents per 100 grams.

To a 4-neck round-bottom flask equipped with a mechanical stirrer, anitrogen inlet to maintain a nitrogen blanket, a water-cooled condenser,and a thermocouple connected to heating control device and a heatingmantle is added 30 parts of the diglycidyl ether of4,4′-(1,4-Phenylenebis(propane-2,2-diyl))diphenol, 20.7 parts of4,4′-(1,4-Phenylenebis(propane-2,2-diyl))diphenol (or, alternatively, asuitable amount of any other upgrade dihydric phenol such as, e.g.,hydroquinone), 0.05 parts polymerization catalyst, and 2.66 partsmethylisobutyl ketone. This mixture is heated with stirring to 125° C.,allowed to exotherm, and is then heated at 160° C. for 3 hours until theepoxy value is 0.032 eq/100 g. At this point to the mixture is added 48parts cyclohexanone, while the mixture is cooled to 70° C. The batch isdischarged affording a solvent-based polymer with a nonvolatile contentof 50% and an Epoxy value of 0.030 eq/100 grams.

A packaging coating composition may be formulated pursuant to themethods and materials included herein using the resulting polyetherpolymer.

This application incorporates by reference the disclosures of each ofthe following: the U.S. continuation-in-part application entitled“COATING COMPOSITIONS FOR CONTAINERS AND OTHER ARTICLES AND METHODS OFCOATING” (application Ser. No. 13/570,743, now U.S. Pat. No. 11,053,409B2) filed on Aug. 9, 2012; U.S. Provisional Application entitled“COATING COMPOSITIONS FOR CONTAINERS AND OTHER ARTICLES AND METHODS OFCOATING” (Application No. 61/681,394) filed on Aug. 9, 2012; and U.S.Provisional Application entitled “COATING COMPOSITIONS FOR CONTAINERSAND OTHER ARTICLES AND METHODS OF COATING” (Application No. 61/681,434)filed on Aug. 9, 2012.

The complete disclosure of all patents, patent applications, andpublications, and electronically available material cited herein areincorporated by reference. The foregoing detailed description andexamples have been given for clarity of understanding only. Nounnecessary limitations are to be understood therefrom. The invention isnot limited to the exact details shown and described, for variationsobvious to one skilled in the art will be included within the inventiondefined by the claims. The invention illustratively disclosed hereinsuitably may be practiced, in some embodiments, in the absence of anyelement which is not specifically disclosed herein.

What is claimed is:
 1. A beverage can end coil coating compositioncomprising: a water-based coating composition comprising a lubricant anda polyether polymer that has a glass transition temperature of at least60° C. and is present as a portion of a polyether-acrylic copolymer;wherein the polyether polymer portion has a number average molecularweight of at least 2,000, does not include any structural units derivedfrom bisphenol A, bisphenol F, bisphenol S, or any diepoxides thereof,and does not include any structural units derived from a polyhydricphenol having estrogenic agonist activity greater than or equal to thatof bisphenol S, and wherein the polyether polymer portion includes aplurality of segments of the below Formula (I) dispersed throughout abackbone of the polyether polymer portion:

wherein: each of the oxygen atoms depicted in Formula (I) is present inan ether linkage; H denotes a hydrogen atom, if present; the segment ofFormula (I) does not include any halogen atoms; each R¹ is independentlyan atom or group having an atomic weight of at least 15 Daltons; v isindependently 2 to 4, and wherein the depicted phenylene group(s)include an R¹ group located at each ortho ring position relative to eachdepicted oxygen atom; w is 4; R², if present, comprises acarbon-containing group, a sulfur-containing group, an oxygen-containinggroup, a nitrogen-containing group, or a combination thereof, with theproviso that that if R² has a structure of the formula —C(R⁷)(R⁸) —,where R⁷ and R⁸ are each independently a hydrogen atom, an organicgroup, a sulfur-containing group, a nitrogen-containing group, or anyother suitable group that is substantially non-reactive with an epoxygroup, and wherein R⁷ and R⁸ can optionally join to form a cyclic group,then R² has a molecular weight of (i) less than 42 Daltons or (ii)greater than 125 Daltons to less than 500 Daltons; n is 0 or 1; with theproviso that if n is 0, the phenylene groups depicted in Formula (I) canoptionally join to form a fused ring system in which case w is 3; t is 0or 1; and two or more R¹ or R² groups can join to form one or morecyclic groups; and wherein the polyether polymer portion includes aplurality of segments of Formula (I) in which t is
 1. 2. The coatingcomposition of claim 1, wherein the lubricant comprises a wax,polytetrafluoroethylene (PTFE) or polyethylene lubricant.
 3. The coatingcomposition of claim 1, wherein the lubricant is present in the coatingcomposition in an amount of at least 0.1 wt. % and no greater than 2 wt.% based on the total weight of nonvolatile material in the coatingcomposition.
 4. The coating composition of claim 1, wherein R² has amolecular weight less than 42 Daltons.
 5. The coating composition ofclaim 1, wherein R² is —CH₂—.
 6. The coating composition of claim 1,wherein R² has a molecular weight greater than 125 Daltons to less than500 Daltons.
 7. The coating composition of claim 1, wherein R² includes10 to 15 carbon atoms.
 8. The coating composition of claim 1, whereineach depicted oxygen atom in Formula (I) is located at a para positionrelative to R².
 9. The coating composition of claim 1, wherein each R¹is independently a methyl moiety.
 10. The coating composition of claim1, wherein t is
 1. 11. The coating composition of claim 1, wherein thepolyether polymer portion includes at least 25% by weight of phenylenegroups, and wherein the polyether polymer includes —CH₂—CH(OH)—CH₂— or—CH₂—CH₂—CH(OH)— segments.
 12. The coating composition of claim 1,wherein the segments of Formula (I) constitute at least 30% by weight ofthe polyether polymer portion.
 13. The coating composition of claim 1,wherein the polyether polymer portion has a glass transition temperatureof at least 70° C.
 14. The coating composition of claim 1, wherein thepolyether polymer portion is completely free of bound polyhydricphenols, or epoxides thereof, having estrogenic activity greater thanthat of 4,4′-(propane-2,2-diyl)bis(2,6-dibromophenol).
 15. The coatingcomposition of claim 1, wherein the polyether polymer portion does notinclude any segments of Formula (I) in which R² includes ester linkagesin a backbone of R² connecting the pair of depicted phenylene groups.16. The coating composition of claim 1, wherein the polyether polymerportion is prepared from ingredients including: (i) an upgrade dihydricphenol that is free of bisphenol A and does not exhibit appreciableestrogenic activity, and (ii) a diepoxide compound that includes asegment of Formula (I).
 17. The coating composition of claim 16, whereinthe upgrade dihydric phenol comprises hydroquinone, catechol,resorcinol, a substituted variant thereof, or a mixture thereof.
 18. Thecoating composition of claim 16, wherein the upgrade dihydric phenolincludes one or more ester linkages.
 19. The coating composition ofclaim 16, wherein the diepoxide compound is non-genotoxic and is derivedfrom a dihydric phenol that that exhibits a log Relative ProliferativeEffect value in the MCF-7 cell proliferation assay of less than −3. 20.The coating composition of claim 1, wherein the polyether-acryliccopolymer is covalently attached to one or more oligomers or polymershaving salt or salt-forming groups to render the polymerwater-dispersible.
 21. The coating composition of claim 1, wherein thepolyether-acrylic copolymer is a water-dispersible polymer formed in thepresence of an amine from preformed polymers comprising (a) a preformedoxirane-functional polymer having at least one segment of Formula (I)and (b) an acid-functional polymer.
 22. The coating composition of claim1, wherein the polyether-acrylic copolymer is a water-dispersiblepolymer formed from an oxirane-functional polyether polymer having atleast one segment of Formula (I) that is reacted with ethylenicallyunsaturated monomers to form an acid-functional polymer.
 23. The coatingcomposition of claim 1, wherein the polyether-acrylic copolymer is awater-dispersible polymer having the structure E-L-A, wherein E is aportion formed from the polyether polymer, A is a polymerized acrylicportion, and L is a linking portion that covalently links E to A; andwherein L is formed from an unsaturated linking compound having (i)either conjugated carbon-carbon double bonds or a carbon-carbon triplebond and (ii) a functional group capable of reacting with an oxiranegroup.
 24. The coating composition of claim 1, wherein thepolyether-acrylic copolymer is acid-functional.
 25. The coatingcomposition of claim 1, wherein the polyether-acrylic copolymer is abinder polymer constituting at least 50 wt. % and less than about 90 wt.% of the coating composition, based on the total weight of resin solidsin the coating composition.
 26. The coating composition of claim 1,wherein the coating composition includes at least about 5 wt. % and lessthan about 30 wt. % of an acrylic component as determined by an amountof a monomer mixture used to prepare the acrylic component and based onthe total weight of resin solids in the coating system.
 27. The coatingcomposition of claim 1, wherein the coating composition contains atleast 15 wt. % and no greater than 50 wt. % non-volatile components. 28.The coating composition of claim 1, wherein the coating composition,when applied to chrome-treated aluminum substrate and baked for 60seconds at 241° C. temperature to achieve a dried film thickness of 7milligrams per square inch and formed into a fully converted riveted 202standard opening beverage can end, passes less than 5 milliamps ofcurrent after being exposed for 4 seconds to a room-temperatureelectrolyte solution containing 1% by weight of NaCl dissolved indeionized water.
 29. The coating composition of claim 28, wherein thedried film on the fully converted riveted 202 standard opening beveragecan end is capable of withstanding being immersed in a 2% aqueous NaClsolution for 90 minutes at a temperature of 121° C. and a pressure of1.05 kilograms per square centimeter without exhibiting any blisteringor loss of adhesion.
 30. The coating composition of claim 1, wherein: nis 1, and R² comprises a carbon-containing group.
 31. The coatingcomposition of claim 1, wherein the polyether polymer includes aplurality of segments derived from4,4′-methylenebis(2,6-dimethylphenol).
 32. A coated riveted beverage canend having thereon a dried film of a coating composition according toclaim
 1. 33. A method for making a coated riveted beverage can endcomprising the steps of: a) applying to an aluminum coil substrate awater-based coating composition comprising a polyether polymer that hasa glass transition temperature of at least 60° C. and is present as aportion of a polyether-acrylic copolymer; wherein the polyether polymerportion has a number average molecular weight of at least 2,000, doesnot include any structural units derived from bisphenol A, bisphenol F,bisphenol S, or any diepoxides thereof, and does not include anystructural units derived from a polyhydric phenol having estrogenicagonist activity greater than or equal to that of bisphenol S, andwherein the polyether polymer portion includes a plurality of segmentsof the below Formula (I) dispersed throughout a backbone of thepolyether polymer portion:

wherein: each of the oxygen atoms depicted in Formula (I) is present inan ether linkage; the segment of Formula (I) does not include anyhalogen atoms; each R¹ is independently an atom or group having anatomic weight of at least 15 Daltons; v is independently 2 to 4, andwherein the depicted phenylene group(s) include an R¹ group located ateach ortho ring position relative to each depicted oxygen atom; w is 4;R², if present, comprises a carbon-containing group, a sulfur-containinggroup, an oxygen-containing group, a nitrogen-containing group, or acombination thereof, with the proviso that that if le has a structure ofthe formula —C(R⁷)(R⁸) —, where R⁷ and R⁸ are each independently ahydrogen atom, an organic group, a sulfur-containing group, anitrogen-containing group, or any other suitable group that issubstantially non-reactive with an epoxy group, and wherein R⁷ and R⁸can optionally join to form a cyclic group, then le has a molecularweight of (i) less than 42 Daltons or (ii) greater than 125 Daltons toless than 500 Daltons; n is 0 or 1; with the proviso that if n is 0, thephenylene groups depicted in Formula (I) can optionally join to form afused ring system in which case w is 3; t is 0 or 1; and two or more R¹or R² groups can join to form one or more cyclic groups; and wherein thepolyether polymer portion includes a plurality of segments of Formula(I) in which t is 1; b) hardening the coating composition; and c)forming the substrate into a coated riveted beverage can end.
 34. Themethod of claim 33, wherein the coating composition further comprises alubricant.
 35. The method of claim 34, wherein the lubricant comprises awax, polytetrafluoroethylene (PTFE) or polyethylene lubricant.
 36. Themethod of claim 34, wherein the lubricant is present in the coatingcomposition in an amount of at least 0.1 wt. % and no greater than 2 wt.% based on the total weight of nonvolatile material in the coatingcomposition.
 37. The method of claim 33, wherein the coatingcomposition, when applied to chrome-treated aluminum substrate and bakedfor 60 seconds at 241° C. temperature to achieve a dried film thicknessof 7 milligrams per square inch and formed into a fully convertedriveted 202 standard opening beverage can end, passes less than 5milliamps of current after being exposed for 4 seconds to aroom-temperature electrolyte solution containing 1% by weight of NaCldissolved in deionized water.
 38. The method of claim 37, wherein thedried film on the fully converted riveted 202 standard opening beveragecan end is capable of withstanding being immersed in a 2% aqueous NaClsolution for 90 minutes at a temperature of 121° C. and a pressure of1.05 kilograms per square centimeter without exhibiting any blisteringor loss of adhesion.